Savignygrin, a Platelet Aggregation Inhibitor from the Soft TickOrnithodoros savignyi, Presents the RGD Integrin Recognition Motif on the Kunitz-BPTI Fold

Savignygrin, a platelet aggregation inhibitor that possesses the RGD integrin recognition motif, has been purified from the soft tick Ornithodoros savignyi. Two isoforms with similar biological activities differ because of R52G and N60G in their amino acid sequences, indicating a recent gene duplication event. Platelet aggregation induced by ADP (IC50, 130 nm), collagen, the thrombin receptor-activating peptide, and epinephrine was inhibited, although platelets were activated and underwent a shape change. The binding of α-CD41 (P2) to platelets, the binding of purified αIIbβ3 to fibrinogen, and the adhesion of platelets to fibrinogen was inhibited, indicating a targeting of the fibrinogen receptor. In contrast, the adhesion of osteosarcoma cells that express the integrin αvβ3 to vitronectin or fibrinogen was not inhibited, indicating the specificity of savignygrin toward αIIbβ3. Savignygrin shows sequence identity to disagregin, a platelet aggregation inhibitor from the tickOrnithodoros moubata that lacks an RGD motif. The cysteine arrangement of savignygrin is similar to that of the bovine pancreatic trypsin inhibitor family of serine protease inhibitors. A homology model based on the structure of the tick anticoagulant peptide indicates that the RGD motif is presented on the substrate-binding loop of the canonical BPTI inhibitors. However, savignygrin did not inhibit the serine proteases fXa, plasmin, thrombin, or trypsin. This is the first report of a platelet aggregation inhibitor that presents the RGD motif using the Kunitz-BPTI protein fold. Savignygrin, a platelet aggregation inhibitor that possesses the RGD integrin recognition motif, has been purified from the soft tick Ornithodoros savignyi. Two isoforms with similar biological activities differ because of R52G and N60G in their amino acid sequences, indicating a recent gene duplication event. Platelet aggregation induced by ADP (IC50, 130 nm), collagen, the thrombin receptor-activating peptide, and epinephrine was inhibited, although platelets were activated and underwent a shape change. The binding of α-CD41 (P2) to platelets, the binding of purified αIIbβ3 to fibrinogen, and the adhesion of platelets to fibrinogen was inhibited, indicating a targeting of the fibrinogen receptor. In contrast, the adhesion of osteosarcoma cells that express the integrin αvβ3 to vitronectin or fibrinogen was not inhibited, indicating the specificity of savignygrin toward αIIbβ3. Savignygrin shows sequence identity to disagregin, a platelet aggregation inhibitor from the tickOrnithodoros moubata that lacks an RGD motif. The cysteine arrangement of savignygrin is similar to that of the bovine pancreatic trypsin inhibitor family of serine protease inhibitors. A homology model based on the structure of the tick anticoagulant peptide indicates that the RGD motif is presented on the substrate-binding loop of the canonical BPTI inhibitors. However, savignygrin did not inhibit the serine proteases fXa, plasmin, thrombin, or trypsin. This is the first report of a platelet aggregation inhibitor that presents the RGD motif using the Kunitz-BPTI protein fold. coagulation factor Xa tick anticoagulant peptide bovine pancreatic trypsin inhibitor dithiothreitol thrombin receptor-activating peptide fluorescein isothiocyanate size exclusion high performance liquid chromatography anion exchange high performance liquid chromatography reversed phase high performance liquid chromatography electrospray mass spectrometry matrix-assisted laser desorption ionization time of flight mass spectrometry untranslated region rapid amplification of cDNA ends root mean square deviation Integrins are a family of adhesion receptors that propitiates cell-cell and cell-matrix interactions. Numerous physiological processes like hemostasis, fertilization, neuron-neuron interaction, and inflammation are mediated by integrins (1Clemetson K.J. Cell. Mol. Life Sci. 1998; 54: 499-501Crossref Scopus (5) Google Scholar). The functional receptor is expressed as a transmembrane heterodimer consisting of α and β subunits. To date, 17 α and 8 β subunits have been identified and form, in various permutations, more than 20 described integrins (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar). Different combinations of subunits convey specificity for ligands (collagen-α2β1, fibronectin-α5β1, laminin-α6β1, vitronectin-αvβ3, and fibrinogen-αIIbβ3), although αIIbβ3 can also recognize fibronectin, vitronectin, von Willebrand's factor, and prothrombin (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar). Most ligands recognized by integrins contain the integrin recognition motif RGD (3Ruoslahti E. Pierschbacher M.D. Science. 1987; 238: 491-497Crossref PubMed Scopus (3841) Google Scholar). Some ligands may also contain other sequences recognized by integrins such as the dodecapeptide sequence HHLGGAKQAGDV from the γ-chain of fibrinogen that binds to αIIbβ3 (4Andrieux A. Hudry-Clergeon G. Ryckewaert J.J. Chapel A. Ginsberg M.H. Plow E.F. Marguerie G. J. Biol. Chem. 1989; 264: 9258-9265Abstract Full Text PDF PubMed Google Scholar).αIIbβ3 (GPIIbIIIa) is the major integrin of platelets and the only adhesion receptor capable of mediating platelet aggregation by the binding of fibrinogen or von Willebrand's factor (5Calvete J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google Scholar, 6Calvete J.J. Proc. Biol. PubMed Scopus Google Scholar, E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). platelets, αIIbβ3 in an that binds to the γ-chain dodecapeptide of fibrinogen (5Calvete J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google Scholar). The also has a to that contain or are presented on recognition from the protein J.J. Proc. Biol. PubMed Scopus Google Scholar). The can also by RGD from the of PubMed Google Scholar). that the binding in αIIbβ3 may a the protein J.J. Proc. Biol. PubMed Scopus Google Scholar). platelet by various αIIbβ3 a that the binding of that contain the RGD motif. The is and is by and subunits. A the with as in the RGD motif (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google for integrins have for the of integrin and the of E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). The are the that are in the of by the of platelet aggregation J.J. Proc. Biol. PubMed Scopus Google Scholar). Platelet aggregation is by the of fibrinogen binding to integrin are a family of mass that the RGD motif for the sequence Cell. Mol. Life Sci. 1998; 54: PubMed Scopus Google Scholar). Most inhibit platelet aggregation with than the because of the of the RGD motif J. Biol. Chem. Full Text PDF PubMed Google Scholar). The of the and the have been in with the of PubMed Scopus Google Scholar, G. Science. PubMed Scopus Google Scholar, J. Mol. Biol. PubMed Scopus Google Scholar, Biol. 1994; Scopus Google Scholar, G. J. Science. 1994; 264: PubMed Scopus Google Scholar). not a structure a consisting of by with a loop region that presents the RGD motif. The sequences the RGD motif as as the of the RGD motif the of the loop have been to to specificity for integrins A. J. Biol. Chem. Full Text PDF PubMed Google to the family to to αIIbβ3 have been described for and soft J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). The inhibitor from the a RGD motif that is not by cysteine in J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). from the soft tick Ornithodoros moubata RGD and was that the sequence with binding to αIIbβ3. This indicates an from J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar). of the coagulation serine proteases of the have also been described for soft and and thrombin and J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar). the bovine pancreatic trypsin inhibitor although the of differ from of the canonical inhibitors. canonical a substrate-binding loop to the of their the tick their sequences the J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar, PubMed Scopus Google Scholar). This the platelet aggregation inhibitor from the soft tick Ornithodoros that presents RGD motif on the substrate-binding loop of the canonical BPTI inhibitors. The of the RGD motif in the BPTI presents a protein that can for integrin of the of the is for tick of the are an of the of Scopus Google Scholar). are a of of coagulation and platelet of the serine proteases and thrombin have been J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar). platelet aggregation by the of has also been 1998; PubMed Scopus Google Scholar, J. 2000; PubMed Scopus Google Scholar, 1998; Scopus Google Scholar, Scopus Google Scholar). platelet aggregation and αIIbβ3 have been described J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar, J. Biol. Chem. Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar). This a platelet aggregation that is to inhibit platelets by targeting the platelet integrin αIIbβ3. This is the first described platelet aggregation inhibitor from soft with an RGD integrin recognition motif that is presented on the canonical substrate-binding loop of the Kunitz-BPTI isoforms from were in 20 that the are gene and not not isoforms were for disagregin, and in the and J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that the gene duplication is a recent that the of tick from a The of the isoforms is more as sequences were that the However, is not to of a protein are for that are chromatography and high of that as as are J. PubMed Scopus Google is not by sequence or as by similar for This for in by the RGD motif that is in are activated by various receptors and in the of aggregation the binding of fibrinogen J.J. Proc. Biol. PubMed Scopus Google Scholar). Platelet is by a shape from a to a the of and the of platelet A. 1987; PubMed Google Scholar). The of platelets with savignygrin was by a in the of platelet aggregation induced by various of platelets with savignygrin with ADP the to shape with 1989; PubMed Scopus Google Scholar). This by the and the of platelet the integrin αIIbβ3. The of the binding of in the or of ADP that to as as to activated αIIbβ3. The targeting of αIIbβ3 was by the of αIIbβ3 binding to The for savignygrin αvβ3 and also for J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that of platelet aggregation are integrin The BPTI to was that the binding of the RGD to platelets, an with the J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This is by the of an RGD motif in the sequence of has a motif, and peptide that the peptide not inhibit platelet a induced by the structure of for C.S. PubMed Scopus Google Scholar). This is by the of savignygrin on for the of an biological BPTI has also been to as a in form, in the of Mol. Biol. PubMed Scopus Google Scholar). The sequence to the RGD motif of savignygrin is similar to that of that the sequence the RGD motif have an on is the that are is that with the the αIIbβ3 (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar, 6Calvete J.J. Proc. Biol. PubMed Scopus Google Scholar). was also that can inhibit the binding of the dodecapeptide sequence of to αIIbβ3 J. PubMed Scopus Google Scholar). other binding for αIIbβ3 from the RGD motif in the structure are in with the This is by the for the and in the of and is the that the region the motif is the and However, structure is in are for or functional that region is for The as the a binding BPTI is with serine protease PubMed Scopus Google Scholar). This that the not inhibit serine This with the of the substrate-binding loop of the to the platelet fibrinogen receptor. that not inhibit serine proteases a of in by targeting the of the and J. Mol. Biol. PubMed Scopus Google have biological tick to Scopus Google Scholar). are to the a peptide in their from are to the and by or in in are and are in because of the in the 1989; PubMed Scopus Google Scholar, G. J. Biol. PubMed Scopus Google Scholar, J. Mol. PubMed Scopus Google Scholar). The of a peptide in the sequences of savignygrin and the that are in that the are to the has been described for or J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1994; Full Text PDF PubMed Google a amino acid platelet aggregation inhibitor from the tick a RGD motif in the of sequence J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). is amino acid sequence and and the of the RGD motif is This that platelet aggregation with have the of and soft This that the tick have to their to are to a of This in the of a of E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). Savignygrin and a protein that can in The of RGD on the BPTI to that coagulation and platelet aggregation Integrins are a family of adhesion receptors that propitiates cell-cell and cell-matrix interactions. Numerous physiological processes like hemostasis, fertilization, neuron-neuron interaction, and inflammation are mediated by integrins (1Clemetson K.J. Cell. Mol. Life Sci. 1998; 54: 499-501Crossref Scopus (5) Google Scholar). The functional receptor is expressed as a transmembrane heterodimer consisting of α and β subunits. To date, 17 α and 8 β subunits have been identified and form, in various permutations, more than 20 described integrins (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar). Different combinations of subunits convey specificity for ligands (collagen-α2β1, fibronectin-α5β1, laminin-α6β1, vitronectin-αvβ3, and fibrinogen-αIIbβ3), although αIIbβ3 can also recognize fibronectin, vitronectin, von Willebrand's factor, and prothrombin (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar). Most ligands recognized by integrins contain the integrin recognition motif RGD (3Ruoslahti E. Pierschbacher M.D. Science. 1987; 238: 491-497Crossref PubMed Scopus (3841) Google Scholar). Some ligands may also contain other sequences recognized by integrins such as the dodecapeptide sequence HHLGGAKQAGDV from the γ-chain of fibrinogen that binds to αIIbβ3 (4Andrieux A. Hudry-Clergeon G. Ryckewaert J.J. Chapel A. Ginsberg M.H. Plow E.F. Marguerie G. J. Biol. Chem. 1989; 264: 9258-9265Abstract Full Text PDF PubMed Google Scholar). αIIbβ3 (GPIIbIIIa) is the major integrin of platelets and the only adhesion receptor capable of mediating platelet aggregation by the binding of fibrinogen or von Willebrand's factor (5Calvete J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google Scholar, 6Calvete J.J. Proc. Biol. PubMed Scopus Google Scholar, E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). platelets, αIIbβ3 in an that binds to the γ-chain dodecapeptide of fibrinogen (5Calvete J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google Scholar). The also has a to that contain or are presented on recognition from the protein J.J. Proc. Biol. PubMed Scopus Google Scholar). The can also by RGD from the of PubMed Google Scholar). that the binding in αIIbβ3 may a the protein J.J. Proc. Biol. PubMed Scopus Google Scholar). platelet by various αIIbβ3 a that the binding of that contain the RGD motif. The is and is by and subunits. A the with as in the RGD motif (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google J.J. Thromb. Haemostasis. 1994; 72: 1-15Crossref PubMed Scopus (177) Google Scholar). for integrins have for the of integrin and the of E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). The are the that are in the of by the of platelet aggregation J.J. Proc. Biol. PubMed Scopus Google Scholar). Platelet aggregation is by the of fibrinogen binding to integrin are a family of mass that the RGD motif for the sequence Cell. Mol. Life Sci. 1998; 54: PubMed Scopus Google Scholar). Most inhibit platelet aggregation with than the because of the of the RGD motif J. Biol. Chem. Full Text PDF PubMed Google Scholar). The of the and the have been in with the of PubMed Scopus Google Scholar, G. Science. PubMed Scopus Google Scholar, J. Mol. Biol. PubMed Scopus Google Scholar, Biol. 1994; Scopus Google Scholar, G. J. Science. 1994; 264: PubMed Scopus Google Scholar). not a structure a consisting of by with a loop region that presents the RGD motif. The sequences the RGD motif as as the of the RGD motif the of the loop have been to to specificity for integrins A. J. Biol. Chem. Full Text PDF PubMed Google Scholar). to the family to to αIIbβ3 have been described for and soft J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). The inhibitor from the a RGD motif that is not by cysteine in J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). from the soft tick Ornithodoros moubata RGD and was that the sequence with binding to αIIbβ3. This indicates an from J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar). of the coagulation serine proteases of the have also been described for soft and and thrombin and J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar). the bovine pancreatic trypsin inhibitor although the of differ from of the canonical inhibitors. canonical a substrate-binding loop to the of their the tick their sequences the J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar, PubMed Scopus Google Scholar). This the platelet aggregation inhibitor from the soft tick Ornithodoros that presents RGD motif on the substrate-binding loop of the canonical BPTI inhibitors. The of the RGD motif in the BPTI presents a protein that can for integrin of the of the is for tick of the are an of the of Scopus Google Scholar). are a of of coagulation and platelet of the serine proteases and thrombin have been J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar). platelet aggregation by the of has also been 1998; PubMed Scopus Google Scholar, J. 2000; PubMed Scopus Google Scholar, 1998; Scopus Google Scholar, Scopus Google Scholar). platelet aggregation and αIIbβ3 have been described J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar, J. Biol. Chem. Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar). This a platelet aggregation that is to inhibit platelets by targeting the platelet integrin αIIbβ3. This is the first described platelet aggregation inhibitor from soft with an RGD integrin recognition motif that is presented on the canonical substrate-binding loop of the Kunitz-BPTI isoforms from were in 20 that the are gene and not not isoforms were for disagregin, and in the and J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that the gene duplication is a recent that the of tick from a The of the isoforms is more as sequences were that the However, is not to of a protein are for that are chromatography and high of that as as are J. PubMed Scopus Google is not by sequence or as by similar for This for in by the RGD motif that is in are activated by various receptors and in the of aggregation the binding of fibrinogen J.J. Proc. Biol. PubMed Scopus Google Scholar). Platelet is by a shape from a to a the of and the of platelet A. 1987; PubMed Google Scholar). The of platelets with savignygrin was by a in the of platelet aggregation induced by various of platelets with savignygrin with ADP the to shape with 1989; PubMed Scopus Google Scholar). This by the and the of platelet the integrin αIIbβ3. The of the binding of in the or of ADP that to as as to activated αIIbβ3. The targeting of αIIbβ3 was by the of αIIbβ3 binding to The for savignygrin αvβ3 and also for J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that of platelet aggregation are integrin The BPTI to was that the binding of the RGD to platelets, an with the J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This is by the of an RGD motif in the sequence of has a motif, and peptide that the peptide not inhibit platelet a induced by the structure of for C.S. PubMed Scopus Google Scholar). This is by the of savignygrin on for the of an biological BPTI has also been to as a in form, in the of Mol. Biol. PubMed Scopus Google Scholar). The sequence to the RGD motif of savignygrin is similar to that of that the sequence the RGD motif have an on is the that are is that with the the αIIbβ3 (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar, 6Calvete J.J. Proc. Biol. PubMed Scopus Google Scholar). was also that can inhibit the binding of the dodecapeptide sequence of to αIIbβ3 J. PubMed Scopus Google Scholar). other binding for αIIbβ3 from the RGD motif in the structure are in with the This is by the for the and in the of and is the that the region the motif is the and However, structure is in are for or functional that region is for The as the a binding BPTI is with serine protease PubMed Scopus Google Scholar). This that the not inhibit serine This with the of the substrate-binding loop of the to the platelet fibrinogen receptor. that not inhibit serine proteases a of in by targeting the of the and J. Mol. Biol. PubMed Scopus Google have biological tick to Scopus Google Scholar). are to the a peptide in their from are to the and by or in in are and are in because of the in the 1989; PubMed Scopus Google Scholar, G. J. Biol. PubMed Scopus Google Scholar, J. Mol. PubMed Scopus Google Scholar). The of a peptide in the sequences of savignygrin and the that are in that the are to the has been described for or J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1994; Full Text PDF PubMed Google a amino acid platelet aggregation inhibitor from the tick a RGD motif in the of sequence J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). is amino acid sequence and and the of the RGD motif is This that platelet aggregation with have the of and soft This that the tick have to their to are to a of This in the of a of E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). Savignygrin and a protein that can in The of RGD on the BPTI to that coagulation and platelet aggregation of the of the is for tick of the are an of the of Scopus Google Scholar). are a of of coagulation and platelet of the serine proteases and thrombin have been J. PubMed Scopus Google Scholar, Scopus Google Scholar, Science. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, A. J. Scopus Google Scholar, Mol. Biol. Google Scholar). platelet aggregation by the of has also been 1998; PubMed Scopus Google Scholar, J. 2000; PubMed Scopus Google Scholar, 1998; Scopus Google Scholar, Scopus Google Scholar). platelet aggregation and αIIbβ3 have been described J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar, J. Biol. Chem. Full Text PDF PubMed Google Scholar, J. PubMed Scopus Google Scholar). This a platelet aggregation that is to inhibit platelets by targeting the platelet integrin αIIbβ3. This is the first described platelet aggregation inhibitor from soft with an RGD integrin recognition motif that is presented on the canonical substrate-binding loop of the Kunitz-BPTI fold. The isoforms from were in 20 that the are gene and not not isoforms were for disagregin, and in the and J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that the gene duplication is a recent that the of tick from a The of the isoforms is more as sequences were that the However, is not to of a protein are for that are chromatography and high of that as as are J. PubMed Scopus Google Scholar). is not by sequence or as by similar for This for in by the RGD motif that is in are activated by various receptors and in the of aggregation the binding of fibrinogen J.J. Proc. Biol. PubMed Scopus Google Scholar). Platelet is by a shape from a to a the of and the of platelet A. 1987; PubMed Google Scholar). The of platelets with savignygrin was by a in the of platelet aggregation induced by various of platelets with savignygrin with ADP the to shape with 1989; PubMed Scopus Google Scholar). This by the and the of platelet the integrin αIIbβ3. The of the binding of in the or of ADP that to as as to activated αIIbβ3. The targeting of αIIbβ3 was by the of αIIbβ3 binding to The for savignygrin αvβ3 and also for J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This that of platelet aggregation are integrin The BPTI to was that the binding of the RGD to platelets, an with the J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). This is by the of an RGD motif in the sequence of has a motif, and peptide that the peptide not inhibit platelet a induced by the structure of for C.S. PubMed Scopus Google Scholar). This is by the of savignygrin on for the of an biological BPTI has also been to as a in form, in the of Mol. Biol. PubMed Scopus Google Scholar). The sequence to the RGD motif of savignygrin is similar to that of that the sequence the RGD motif have an on is the that are is that with the the αIIbβ3 (2Plow E.F Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. J. Biol. Chem. 2000; 275: 21785-21788Abstract Full Text Full Text PDF PubMed Scopus (1100) Google Scholar, 6Calvete J.J. Proc. Biol. PubMed Scopus Google Scholar). was also that can inhibit the binding of the dodecapeptide sequence of to αIIbβ3 J. PubMed Scopus Google Scholar). other binding for αIIbβ3 from the RGD motif in the structure are in with the This is by the for the and in the of and is the that the region the motif is the and However, structure is in are for or functional that region is for The as the a binding The BPTI is with serine protease PubMed Scopus Google Scholar). This that the not inhibit serine This with the of the substrate-binding loop of the to the platelet fibrinogen receptor. that not inhibit serine proteases a of in by targeting the of the and J. Mol. Biol. PubMed Scopus Google Scholar). To have biological tick to Scopus Google Scholar). are to the a peptide in their from are to the and by or in in are and are in because of the in the 1989; PubMed Scopus Google Scholar, G. J. Biol. PubMed Scopus Google Scholar, J. Mol. PubMed Scopus Google Scholar). The of a peptide in the sequences of savignygrin and the that are in that the are to the has been described for or J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). a amino acid platelet aggregation inhibitor from the tick a RGD motif in the of sequence J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). is amino acid sequence and and the of the RGD motif is This that platelet aggregation with have the of and soft This that the tick have to their to are to a of This in the of a of E.F. Cierniewski C.S. Xiao Z. Haas T.A. Byzova T.V. Thromb. Haemostasis. PubMed Scopus Google Scholar). Savignygrin and a protein that can in The of RGD on the BPTI to that coagulation and platelet aggregation J. of for of for the of and and J. for amino acid