Inhibition of the Self-assembly of Collagen I into Fibrils with Synthetic Peptides

A series of experiments were carried out to test the hypothesis that the self-assembly of collagen I monomers into fibrils depends on the interactions of specific binding sites in different regions of the monomer. Six synthetic peptides were prepared with sequences found either in the collagen triple helix or in the N- or C-telopeptides of collagen I. The four peptides with sequences found in the telopeptides were found to inhibit self-assembly of collagen I in a purified in vitro system. At concentrations of 2.5 mm, peptides with sequences in the C-telopeptides of the α1(I) and α2(I) chain inhibited assembly at about 95%. The addition of the peptide with the α2-telopeptide sequence was effective in inhibiting assembly if added during the lag phase and early propagation phase but not later in the assembly process. Experiments with biotinylated peptides indicated that both the N- and C-telopeptides bound to a region between amino acid 776 and 822 of the α(I) chain. A fragment of nine amino acids with sequences in the α2-telopeptide was effective in inhibiting fibril assembly. Mutating two aspartates in the 9-mer peptide to serine had no effect on inhibition of fibril assembly, but mutating two tyrosine residues and one phenylalanine residue abolished the inhibitory action. Molecular modeling of the binding sites demonstrated favorable hydrophobic and electrostatic interactions between the α2telopeptide and residues 781–794 of the α(I) chain. A series of experiments were carried out to test the hypothesis that the self-assembly of collagen I monomers into fibrils depends on the interactions of specific binding sites in different regions of the monomer. Six synthetic peptides were prepared with sequences found either in the collagen triple helix or in the N- or C-telopeptides of collagen I. The four peptides with sequences found in the telopeptides were found to inhibit self-assembly of collagen I in a purified in vitro system. At concentrations of 2.5 mm, peptides with sequences in the C-telopeptides of the α1(I) and α2(I) chain inhibited assembly at about 95%. The addition of the peptide with the α2-telopeptide sequence was effective in inhibiting assembly if added during the lag phase and early propagation phase but not later in the assembly process. Experiments with biotinylated peptides indicated that both the N- and C-telopeptides bound to a region between amino acid 776 and 822 of the α(I) chain. A fragment of nine amino acids with sequences in the α2-telopeptide was effective in inhibiting fibril assembly. Mutating two aspartates in the 9-mer peptide to serine had no effect on inhibition of fibril assembly, but mutating two tyrosine residues and one phenylalanine residue abolished the inhibitory action. Molecular modeling of the binding sites demonstrated favorable hydrophobic and electrostatic interactions between the α2telopeptide and residues 781–794 of the α(I) chain. Fibrillar collagens form the largest protein structures found in complex organisms (see Refs. 1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar and 2Prockop D.J. Kivirikko K.I. Annu. Rev. Biochem. 1995; 64: 403-434Crossref PubMed Scopus (1388) Google Scholar). The most abundant collagen fibrils consist almost entirely of a single monomer of type I collagen. The structure of the monomer was established several decades ago, but the precise pattern of packing of the monomer into fibrils has not been defined and remains controversial (3Smith J.W. Nature. 1968; 219: 157-158Crossref PubMed Scopus (264) Google Scholar, 4Hulmes D.J.S. Miller A. Nature. 1979; 282: 878-880Crossref PubMed Scopus (231) Google Scholar, 5Holmes D.F. Chapman J.A. Biochem. Biophys. Res. Commun. 1979; 87: 993-999Crossref PubMed Scopus (24) Google Scholar, 6Piez K.A. Trus B.L. Biosci. Rep. 1981; 1: 801-810Crossref PubMed Scopus (57) Google Scholar, 7Hulmes D.J.S. Jesior J.-C. Miller A. Berthet-Colominas C. Wolff C. Proc. Natl. Acad. Sci. U. S. A. 1981; 78: 3567-3571Crossref PubMed Scopus (93) Google Scholar, 8Brodsky B. Eikenberry E.F. Methods Enzymol. 1982; 82: 127-173Crossref PubMed Scopus (111) Google Scholar, 9Woodhead-Galloway J. Hukins D.W.L. Connective Tissue Matrix. Verlag Chemie, Basel, Switzerland1984: 133-160Google Scholar, 10Hulmes D.J.S. Holmes D.F. Cummings C. J. Mol. Biol. 1985; 184: 473-477Crossref PubMed Scopus (34) Google Scholar, 11Ward N.P. Hulmes D.J.S. Chapman J.A. J. Mol. Biol. 1986; 190: 107-112Crossref PubMed Scopus (32) Google Scholar, 12Galloway J. Bairoti A. Garrone R. Biology of Invertebrate and Lower Vertebrate Collagens. Plenum Publishing Corp., New York1985: 73-82Crossref Google Scholar, 13Chapman J. Biopolymers. 1989; 28: 1367-1382Crossref PubMed Scopus (61) Google Scholar, 14Jones E.Y. Miller A. J. Mol. Biol. 1991; 218: 209-219Crossref PubMed Scopus (79) Google Scholar, 15Veis A. Payne K. Nimni M.E. Collagen: Biochemistry. CRC Press, Inc., Boca Raton, FL1988: 113-138Google Scholar, 16Gelman R.A. Piez K.A. J. Biol. Chem. 1980; 255: 8098-8102Abstract Full Text PDF PubMed Google Scholar, 17Birk D.E. Zycband E.I. Winkelman D.E. Trelstad R.L. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 4549-4553Crossref PubMed Scopus (140) Google Scholar). Type I collagen is similar to other fibrillar collagen in that it is first synthesized as a soluble procollagen containing N-propeptides and C-propeptides (see Ref. 2Prockop D.J. Kivirikko K.I. Annu. Rev. Biochem. 1995; 64: 403-434Crossref PubMed Scopus (1388) Google Scholar). The propeptides are cleaved by specific N- and C-proteinases to generate the monomers that comprise collagen fibrils. The two α1(I) and one α2(I) chains of a monomer of type I collagen are primarily comprised of about 338 repeating tripeptide sequences of Gly-Xaa-Ybb in which Xaa is frequently proline and Ybb is frequently hydroxyproline. The ends of the α1(I) and one α2(I) chains consist of short telopeptides of about 11–26 amino acids per chain. The distribution of hydrophobic and charged resides in the Xaa and Ybb positions in the triple-helical domain define 4.4 repeats or 4.4 D periods of about 234 amino acids each. In longitudinal sections, the monomers are arranged in fibrils in a head-to-head-to-tail orientation with a gap of about 0.6 D periods and, therefore, repeat of 5 D periods. The continuity of the fibrils is maintained by many of the monomers being staggered by 1, 2, 3, or 4 D periods relative to the nearest neighbor so as to generate gap and overlap regions. However, there are conflicting data from electron microscopy and x-ray analysis about the lateral packing of the monomers. One view is that the monomers are laterally packed in a tilted quasi-hexagonal lattice (4Hulmes D.J.S. Miller A. Nature. 1979; 282: 878-880Crossref PubMed Scopus (231) Google Scholar,14Jones E.Y. Miller A. J. Mol. Biol. 1991; 218: 209-219Crossref PubMed Scopus (79) Google Scholar). A related view is that the fibrils consist of “compressed” microfibrils that are comprised of monomers coiled into a rope-like pentameric structure (3Smith J.W. Nature. 1968; 219: 157-158Crossref PubMed Scopus (264) Google Scholar, 6Piez K.A. Trus B.L. Biosci. Rep. 1981; 1: 801-810Crossref PubMed Scopus (57) Google Scholar). Still another view is that the lateral packing of the collagen in many fibrils is either liquid-like or a biological equivalent of a liquid crystal (12Galloway J. Bairoti A. Garrone R. Biology of Invertebrate and Lower Vertebrate Collagens. Plenum Publishing Corp., New York1985: 73-82Crossref Google Scholar, 13Chapman J. Biopolymers. 1989; 28: 1367-1382Crossref PubMed Scopus (61) Google Scholar). One experimental approach to defining the lateral packing of the monomers was to observe the initial assembly of monomers into fibrils. Early experiments (1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar, 11Ward N.P. Hulmes D.J.S. Chapman J.A. J. Mol. Biol. 1986; 190: 107-112Crossref PubMed Scopus (32) Google Scholar, 15Veis A. Payne K. Nimni M.E. Collagen: Biochemistry. CRC Press, Inc., Boca Raton, FL1988: 113-138Google Scholar) on the reassembly of fibrils from collagen extracted from tissues with acidic buffers suggested that the first structures formed were linear strands of monomers bound by 0.4 D period overlaps (4 D staggers). Other observations with extracted collagens suggested the initial stages involved assembly of structures similar to pentameric microfibrils (1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar, 15Veis A. Payne K. Nimni M.E. Collagen: Biochemistry. CRC Press, Inc., Boca Raton, FL1988: 113-138Google Scholar, 16Gelman R.A. Piez K.A. J. Biol. Chem. 1980; 255: 8098-8102Abstract Full Text PDF PubMed Google Scholar). Subsequently, a system was developed for studying assembly of type I collagen fibrils de novo by enzymic cleavage of a purified soluble precursor of procollagen under physiological conditions (18Miyahara M. Njieha F.K. Prockop D.J. J. Biol. Chem. 1982; 257: 8442-8448Abstract Full Text PDF PubMed Google Scholar, 19Kadler K.E. Hojima Y. Prockop D.J. J. Biol. Chem. 1987; 262: 15696-15701Abstract Full Text PDF PubMed Google Scholar, 20Kadler K.E. Hulmes D.J.S. Hojima Y. Prockop D.J. Ann. N. Y. Acad. Sci. 1990; 580: 214-224Crossref PubMed Scopus (45) Google Scholar, 21Kadler K.E. Hojima Y. Prockop D.J. Biochem. J. 1990; 268: 339-343Crossref PubMed Scopus (90) Google Scholar). Because thick fibrils were generated in the system at 30–32 °C, it was possible to use dark-field light microscopy to follow the growth of the fibrils through intermediate stages (21Kadler K.E. Hojima Y. Prockop D.J. Biochem. J. 1990; 268: 339-343Crossref PubMed Scopus (90) Google Scholar). The first fibrils detected had a blunt end and a pointed end or tip. Initial growth of the fibrils was exclusively from the pointed or α tip. Later, β tips appeared on the blunt ends of the fibrils, and the fibrils grew from both directions. Scanning transmission electron microscopy indicated that both the α tips and β tips were near-paraboloidal in shape (22Holmes D.F. Chapman J.A. Prockop D.J. Kadler K.E. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 9855-9859Crossref PubMed Scopus (79) Google Scholar). Also, the monomers were oriented with their N termini directed toward the tips. Subsequent experiments in the same system with type II collagen suggested that the fibrils also grew from pointed tips. However, the monomers were oriented with a C termini directed toward the tips (23Fertala A. Holmes D.F. Kadler K.E. Sieron A.L. Prockop D.J. J. Biol. Chem. 1996; 271: 14864-14869Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar). Also, the fibrils contained central regions in which the monomers were packed symmetrically. Recent observations indicate there may be differences between collagen fibrils assembled in vitro and those assembled in vivo (24Kadler K.E. Holmes D.F. Trotter J.A. Chapman J.A. Biochem. J. 1996; 316: 1-11Crossref PubMed Scopus (1097) Google Scholar). In particular, collagen I fibrils assembled in vitro are exclusively bipolar, but fibrils from tissues are both bipolar and unipolar. Also, intermediates such as pNcollagen may participate in the initial steps of fibril assembly. All the are with the that the fibrils from pointed tips. different were to the growth of fibrils from near-paraboloidal tips. One Miller J. R. Prockop D.J. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: PubMed Scopus Google Scholar) was on the that the initial of the fibril was a pentameric and that the fibril grew by the addition of monomers in a of the suggested that as as two specific binding steps were first for assembly of the and a with about the same as the assembly of the the fibril grew from the by the addition of monomers through one of the two binding A and related D.J.S. Prockop D.J. Biophys. J. 1995; Full Text PDF PubMed Scopus Google Scholar) suggested that assembly with of and monomers were added in strands to generate the tips. The had the that it the first for x-ray data that indicated that of monomers in fibrils were laterally packed in a tilted lattice (4Hulmes D.J.S. Miller A. Nature. 1979; 282: 878-880Crossref PubMed Scopus (231) Google Scholar, 14Jones E.Y. Miller A. J. Mol. Biol. 1991; 218: 209-219Crossref PubMed Scopus (79) Google Scholar). In to the first two a J. Kadler K.E. A. Rev. PubMed Scopus Google Scholar) was developed in which monomers were assembled by a The therefore, that the assembly of monomers into fibrils was similar to such as or of and that the not the of specific binding sites on the monomers. developed a series of experiments on the that the assembly of collagen I monomers into fibrils depends on the interactions of specific binding sites in different regions of the monomers. test the of synthetic peptides on the assembly of fibrils de The synthetic peptides were synthesized and purified by a and of the peptides in experimental conditions were by liquid All the peptides were soluble in the fibril The of peptide was with a of collagen I into fibrils de novo was under conditions (18Miyahara M. Njieha F.K. Prockop D.J. J. Biol. Chem. 1982; 257: 8442-8448Abstract Full Text PDF PubMed Google Scholar, 19Kadler K.E. Hojima Y. Prockop D.J. J. Biol. Chem. 1987; 262: 15696-15701Abstract Full Text PDF PubMed Google Scholar, 20Kadler K.E. Hulmes D.J.S. Hojima Y. Prockop D.J. Ann. N. Y. Acad. Sci. 1990; 580: 214-224Crossref PubMed Scopus (45) Google Scholar, 21Kadler K.E. Hojima Y. Prockop D.J. Biochem. J. 1990; 268: 339-343Crossref PubMed Scopus (90) Google Scholar, A. Holmes D.F. Kadler K.E. Sieron A.L. Prockop D.J. J. Biol. Chem. 1996; 271: 14864-14869Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar). In type I procollagen was from the of and was purified with two steps to The type I procollagen was to I by cleavage with procollagen purified from of The was on a assembly was in a in a with a and containing a physiological and procollagen purified from inhibitory peptides were added to the to concentrations of in 5 of for to at °C, the was for The and were by on a in and the was either with a Molecular or by with and analysis with a Molecular the was carried out in a on a and by dark-field light microscopy Type I collagen extracted with acid from was with and the α chains were by in generate containing α1(I) and α2(I) chains were into and α chains were with or in acid at The were with containing peptides from collagen α chains were into the of the prepared with a and with the was at 4 a binding of telopeptides to collagen the by R. Y. Y. Tissue Scopus Google Scholar) was The were with and with of 5 peptide that was at the N with for by The was with containing and with a of with The were detected by to x-ray for to generate of type I from was cleaved with of from from J. of for at in a of of and the of a of and in the same was and the was at for The was with The was by on a in and with the same as the define the binding with a 3, were of the containing of collagen in was added to and the were at a with were The were with and binding sites were with the were prepared that contained biotinylated or peptide with peptide a peptide was at concentrations from to The peptide were added into containing and the were at for The were with containing biotinylated peptides bound to collagen to was added at of the were with containing and the in was of the was with a Molecular modeling was on a system the The of the collagen I triple helix fragment sequence from and was carried out as by A. J. 1995; Scopus Google Scholar). The of peptide was All the were a and to repeating of and C. S. J. Chem. Scopus Google Scholar). of peptide with the collagen I binding of was to possible binding and electrostatic of the were Six synthetic peptides were prepared on the of two (see Ref. 1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar) had demonstrated that the telopeptides were to be on the monomers to generate packed fibrils, and the self-assembly of collagen monomers is (see Ref. 19Kadler K.E. Hojima Y. Prockop D.J. J. Biol. Chem. 1987; 262: 15696-15701Abstract Full Text PDF PubMed Google and therefore, specific binding sites in the triple helix are to be found in hydrophobic indicated in 1, one peptide contained hydrophobic sequences found the end of the period of the α2(I) a peptide had hydrophobic sequences found the of the period of the α2(I) chain. contained sequences that the cleavage of in the period of the α1(I) chain. The peptides had the sequences of the and by demonstrated that of the peptides were under experimental conditions not The peptides were added in concentrations of 2.5 to the system for fibril by the cleavage of with (18Miyahara M. Njieha F.K. Prockop D.J. J. Biol. Chem. 1982; 257: 8442-8448Abstract Full Text PDF PubMed Google Scholar, 19Kadler K.E. Hojima Y. Prockop D.J. J. Biol. Chem. 1987; 262: 15696-15701Abstract Full Text PDF PubMed Google Scholar, 20Kadler K.E. Hulmes D.J.S. Hojima Y. Prockop D.J. Ann. N. Y. Acad. Sci. 1990; 580: 214-224Crossref PubMed Scopus (45) Google Scholar, 21Kadler K.E. Hojima Y. Prockop D.J. Biochem. J. 1990; 268: 339-343Crossref PubMed Scopus (90) Google Scholar, A. Holmes D.F. Kadler K.E. Sieron A.L. Prockop D.J. J. Biol. Chem. 1996; 271: 14864-14869Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar). indicated in and the peptides and if inhibition of fibril assembly. and almost inhibited fibril assembly, inhibited assembly by about under the conditions of the of fibril assembly with the peptide was demonstrated by the in a with dark-field light fibrils appeared was in a of 2.5 3, The of the was demonstrated by a peptide in which the same amino acids found in were assembled in a indicated in the peptide with the sequence had no effect on fibril assembly. in which the of the peptide were indicated that fibril assembly was inhibited about with a of about and almost with 2.5 in the of synthetic I was with for at and peptides were added to the at concentrations of 2.5 were from collagen monomers by and by in from a of same peptide as with sequence of peptides on fibril assembly in of helix to to of in a analysis of collagen I fibrils. was with at for in a in the or of 2.5 were a with dark-field define the for inhibition of fibril assembly by the the peptide was added in a of 2.5 during the lag early propagation or propagation phase of fibril assembly The peptide inhibited fibril if added during the lag inhibited if added during the early propagation and it had of effect if added during the phase of fibril assembly. test the of the binding of the peptides to a series of were carried out with of and a biotinylated of the peptide indicated in the biotinylated peptide not to of However, it bound to α1(I) β chains that α1(I) and The same peptide bound to peptides indicated in the biotinylated bound to the α1(I) chain but not the α2(I) chain. also indicated in the biotinylated telopeptides bound to of the α1(I) chain that amino acid residues was no binding to of the other of biotinylated telopeptides to the α(I) chain and the fragment chain. as in of α1(I) and α2(I) chains and with biotinylated telopeptides and to α1(I) or α2(I) chains with and with biotinylated of the α1(I) of α2(I) of α1(I) and of α2(I) define the binding in the triple A and of type I collagen were prepared and with the biotinylated indicated in and the peptides bound to the fragment of the α1(I) chain. the two α chains of type I collagen between residues and 776 (1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google the binding of the peptides to both and the of the α1(I) chain indicated that the binding is between amino acid 776 and 822 of the α1(I) chain. experiments were primarily on the peptide with the sequence of the it was short and in sequence define the sequences the peptide several were peptides that were the central region of the sequence and were effective as the and and on inhibition of fibril assembly were with two other and and and was that mutating the two aspartates in a 9-mer peptide to serine residues had no effect on inhibition of fibril assembly. However, mutating two and one phenylalanine in the same sequence to serine residues abolished inhibitory and and the binding in the triple helix a peptide was prepared with the sequence of the amino acids in positions 776 to of the The sequence 776 to was primarily it was the most hydrophobic sequence in the region between 776 and 822 that was defined by the experiments with the peptides and the The peptide was in a binding in which collagen was bound to the of a and the were with a of one of the biotinylated telopeptides and concentrations the peptide The binding of the biotinylated peptide was by with indicated in the peptide with binding the C-telopeptides of the α1(I) chain and the α2(I) chain was no for the binding between biotinylated telopeptides and were with the binding of the two by the peptide for the binding of the C-telopeptides to type I collagen. Type I collagen was bound to and with a of a biotinylated and concentrations of the peptide The were by with for binding of the biotinylated of the α1(I) chain for the binding of the from the α2(I) chain the binding of one of the telopeptides to the triple the was first to the of one of the acid fragment of the that inhibited fibril assembly and and Because the and residues to form a hydrophobic on one of the a single was A and of to the region between residues to of α1(I) chain was The possible binding was the The demonstrated a favorable of hydrophobic and electrostatic The a about the self-assembly of type I collagen into fibrils. the assembly not on specific interactions of binding sites in the as suggested by J. Kadler K.E. A. Rev. PubMed Scopus Google the peptides either had no effect on fibril assembly or inhibited the to about the same the demonstrated that several peptides inhibited the process. with observations (see Ref. 1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google peptides with sequences found in the telopeptides were the most The that was most the of the α2(I) fibril assembly if added at or the first of the lag phase but had effect the binding of the in with is for early steps in the assembly such as of a that is for growth of the fibrils. The binding of the C-telopeptides to the region that residues 776 to the monomers in the binding assembly of a (see Refs. 1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar and Miller J. R. Prockop D.J. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: PubMed Scopus Google Scholar). In the binding of the to about the same region of the α1(I) chain as residues 776 to the out of by or of a of 234 the binding of the generate the and that are found many nearest in fibrils assembled in Also, the binding of the not the monomers for of the that between the residue at of the and the residue at of the α1(I) chain (1Piez K.A. Piez K.A. Reddi A.H. Extracellular Matrix Biochemistry. Elsevier Science Publishing Co., Inc., New York1984: 1-40Google Scholar, N. J. Biol. Chem. Full Text PDF PubMed Google Scholar). there are several possible for the binding of the One is that the binding with linear such as those but not with in the that is in the D.F. B. Kadler K.E. J. Biol. Chem. 268: Full Text PDF PubMed Google Scholar, Hulmes D.J.S. J. Mol. Biol. 1982; Scopus Google Scholar, A. Biopolymers. 1979; Scopus Google Scholar, A. J. Biol. Chem. 1981; Full Text PDF PubMed Google Scholar, A. J. Mol. Biol. 1995; PubMed Scopus Google Scholar) and that is both for assembly into fibrils and N. J. Biol. Chem. Full Text PDF PubMed Google Scholar). A is that binding of the that into fibrils and that the structures in the assembly of M. Biochemistry. PubMed Scopus Google Scholar). with indicated that the for the binding of the is about 5 and the of the two are about of and J. in structures assembled by binding through the may a short and may into monomers that fibril assembly through binding of A is that binding through the not in fibril assembly a of a is and it is for lateral growth of the The is with one of the for growth of microfibrils from tips Miller J. R. Prockop D.J. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: PubMed Scopus Google Scholar). The one specific binding by one for assembly of monomers in a to form a and to longitudinal growth of the a binding by a to growth of a of of monomers on the and to lateral growth of the The demonstrated that the binding of the of the α2(I) chain to residues 776 to of the α1(I) chain was directed primarily by hydrophobic mutating two tyrosine residues and one phenylalanine residue in a acid fragment abolished on fibril mutating two residues had no The modeling experiments indicated that there were of the peptide and the triple helix that hydrophobic and electrostatic interactions between the acid fragment and the region between 776 and The region the of the cleavage that has been as a region of the collagen triple helix R.A. Hukins Biochem. Biophys. Res. Commun. PubMed Scopus Google Scholar). Also, J. PubMed Scopus Google Scholar) a synthetic peptide with amino acid residues 776 to from the region and found that it had a to form a with the central sequence that in residues demonstrated R.A. Hukins Biochem. Biophys. Res. Commun. PubMed Scopus Google Scholar) that the peptide inhibited the binding of to collagen at a of the sequence of amino acids in the region may in a of different binding it is that the of the binding the sites defined for or related that may inhibit the assembly of collagen in The to binding sites in the triple helix and the of short of the telopeptides a for The on a of for of