Key points are not available for this paper at this time.
The maturation of Escherichia coli nitrate reductase A requires the incorporation of the Mo-(bis-MGD) cofactor to the apoprotein. For this process, the NarJ chaperone is strictly required (Blasco, F., Dos Santos, J. P., Magalon, A., Frixon, C., Guigliarelli, B., Santini, C. L., and Giordano, G. (1998) Mol. Microbiol. 28, 435–447). We report the first description of protein interactions between molybdenum cofactor biosynthetic proteins (MogA, MoeA, MobA, and MobB) and the aponitrate reductase (NarG) using a bacterial two-hybrid approach. Two conditions have to be satisfied to allow the visualization of the interactions, (i) the presence of an active and mature molybdenum cofactor and (ii) the presence of the NarJ chaperone and of the NarG structural partner subunit, NarH. Formation of tungsten-substituted cofactor prevents the interaction between NarG and the four biosynthetic proteins. Our results suggested that the final stages of molybdenum cofactor biosynthesis occur on a complex made up by MogA, MoeA, MobA, and MobB, which is also in charge with the delivery of the mature cofactor onto the aponitrate reductase A in a NarJ-assisted process. The maturation of Escherichia coli nitrate reductase A requires the incorporation of the Mo-(bis-MGD) cofactor to the apoprotein. For this process, the NarJ chaperone is strictly required (Blasco, F., Dos Santos, J. P., Magalon, A., Frixon, C., Guigliarelli, B., Santini, C. L., and Giordano, G. (1998) Mol. Microbiol. 28, 435–447). We report the first description of protein interactions between molybdenum cofactor biosynthetic proteins (MogA, MoeA, MobA, and MobB) and the aponitrate reductase (NarG) using a bacterial two-hybrid approach. Two conditions have to be satisfied to allow the visualization of the interactions, (i) the presence of an active and mature molybdenum cofactor and (ii) the presence of the NarJ chaperone and of the NarG structural partner subunit, NarH. Formation of tungsten-substituted cofactor prevents the interaction between NarG and the four biosynthetic proteins. Our results suggested that the final stages of molybdenum cofactor biosynthesis occur on a complex made up by MogA, MoeA, MobA, and MobB, which is also in charge with the delivery of the mature cofactor onto the aponitrate reductase A in a NarJ-assisted process. Molybdenum plays a critical role in the biogeochemistry of nitrogen and sulfur and, as such, has been found to be essential in most mammals as well as in plants. It constitutes an essential trace element found associated with a large group of redox active enzymes in eukaryotes, eubacteria and Archaea. With the exception of nitrogenase, molybdenum is present as an ubiquitous basic structure composed of a molybdenum atom coordinated to one or two molecules of a tricyclic pyranopterin forming the molybdenum cofactor (Moco) 1The abbreviations used are: Moco, molybdenum cofactor; MPT, molybdopterin; MGD, molybdopterin guanine dinucleotide. (1Rajagopalan K.V. Johnson J.L. J. Biol. Chem. 1992; 267: 10199-10202Abstract Full Text PDF PubMed Google Scholar). In all organisms studied so far, Moco is synthesized by an ancient, ubiquitous, and highly conserved biosynthetic pathway. Moco biosynthesis has been extensively studied in Escherichia coli by using a combination of biochemical, genetic, and structural approaches. Moco biosynthesis can be divided into three steps, (i) the conversion of a guanine nucleotide to form precursor Z, (ii) the introduction of two sulfur atoms to give molybdopterin (MPT), and (iii) the chelation of molybdenum by MPT thus forming active Moco (2Mendel R.R. Schwarz G. Met. Ions. Biol. Syst. 2002; 39: 317-368PubMed Google Scholar) (see Fig. 1). In prokaryotes, the cofactor can be further modified by the attachment of a nucleotide onto the terminal phosphate group of MPT (1Rajagopalan K.V. Johnson J.L. J. Biol. Chem. 1992; 267: 10199-10202Abstract Full Text PDF PubMed Google Scholar). In E. coli, most of the molybdoenzymes require not only the GMP-modified form of MPT, i.e. MGD (molybdopterin guanine dinucleotide) for their activity but a Mo-(bis-MPT)-based cofactor where one Mo atom is coordinated by four dithiolenes of two MGD molecules (3Boyington J.C. Gladyshev V.N. Khangulov S.V. Stadtman T.C. Sun P.D. Science. 1997; 275: 1305-1308Crossref PubMed Scopus (508) Google Scholar, 4Jormakka M. Tornroth S. Byrne B. Iwata S. Science. 2002; 295: 1863-1868Crossref PubMed Scopus (413) Google Scholar, 5Bertero M.G. Rothery R.A. Palak M. Hou C. Lim D. Blasco F. Weiner J.H. Strynadka N.C. Nat. Struct. Biol. 2003; 10: 681-687Crossref PubMed Scopus (418) Google Scholar, 6Hilton J.C. Rajagopalan K.V. Arch. Biochem. Biophys. 1996; 325: 139-143Crossref PubMed Scopus (46) Google Scholar, 7Chan M.K. Mukund S. Kletzin A. Adams M.W. Rees D.C. Science. 1995; 267: 1463-1469Crossref PubMed Scopus (544) Google Scholar). However, although the synthesis of Mo-MGD is well documented, formation of Mo-(bis-MGD) remains enigmatic. Noteworthy is that the two processes of molybdenum insertion catalyzed by MogA and MoeA proteins (8Hasona A. Ray R.M. Shanmugam K.T. J. Bacteriol. 1998; 180: 1466-1472Crossref PubMed Google Scholar, 9Joshi M.S. Johnson J.L. Rajagopalan K.V. J. Bacteriol. 1996; 178: 4310-4312Crossref PubMed Google Scholar) and of dinucleotide formation catalyzed by MobA (10Palmer T. Vasishta A. Whitty P.W. Boxer D.H. Eur. J. Biochem. 1994; 222: 687-692Crossref PubMed Scopus (48) Google Scholar) seem to be strongly linked (11Nichols J. Rajagopalan K.V. J. Biol. Chem. 2002; 277: 24995-25000Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar). Information about Moco incorporation within apomolybdoenzymes is scarce. So far, nothing is known about the Moco donor or the molecular mechanism of Moco transfer. In prokaryotes, several molybdoenzymes incorporate the cofactor by a process that involves enzyme-specific chaperones. This situation was first noted for maturation of the dissimilatory nitrate reductase A of E. coli where NarJ was shown to be needed (12Palmer T. Santini C.L. Iobbi-Nivol C. Eaves D.J. Boxer D.H. Giordano G. Mol. Microbiol. 1996; 20: 875-884Crossref PubMed Scopus (151) Google Scholar, 13Blasco F. Dos Santos J.P. Magalon A. Frixon C. Guigliarelli B. Santini C.L. Giordano G. Mol. Microbiol. 1998; 28: 435-447Crossref PubMed Scopus (118) Google Scholar). The list of such chaperones has been expanded by TorD required for the maturation of the trimethylamine-N-oxide reductase (14Pommier J. Mejean V. Giordano G. Iobbi-Nivol C. J. Biol. Chem. 1998; 273: 16615-16620Abstract Full Text Full Text PDF PubMed Scopus (116) Google Scholar, 15Ilbert M. Mejean V. Giudici-Orticoni M.T. Samama J.P. Iobbi-Nivol C. J. Biol. Chem. 2003; 278: 28787-28792Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar). The exact function of this new class of proteins is not yet well understood despite an active role in Moco incorporation facilitation (13Blasco F. Dos Santos J.P. Magalon A. Frixon C. Guigliarelli B. Santini C.L. Giordano G. Mol. Microbiol. 1998; 28: 435-447Crossref PubMed Scopus (118) Google Scholar, 16Ilbert M. Mejean V. Iobbi-Nivol C. Microbiology. 2004; 150: 935-943Crossref PubMed Scopus (61) Google Scholar). Another participant in such a process is the Moco carrier defined as a molecule linking Moco biosynthesis to its subsequent incorporation into various apomolybdoenzymes (17Amy N.K. Rajagopalan K.V. J. Bacteriol. 1979; 140: 114-124Crossref PubMed Google Scholar). However, little is known concerning the identity of this carrier molecule. Interestingly, mutations affecting the activity of E. coli molybdoenzymes mapped only in loci involved in Mo transport (mod) or Moco biosynthesis (moa, mob, moe, and mog) (18Stewart V. MacGregor C.H. J. Bacteriol. 1982; 151: 788-799Crossref PubMed Google Scholar). Such an observation indicates that Mo proteins could ensure Moco protection until its delivery to the apoenzymes. Recent work (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) has shown that, in vivo, numerous protein-protein interactions exist among mo gene products involved in the final stages of Moco biosynthesis and that some of them even require the binding of Moco intermediates to occur. One can envision that these steps occur on a multiprotein complex allowing a fast and protected transfer of oxygen-sensitive intermediates and subsequent delivery of active Moco to resident apomolybdoenzymes. In this work, we provided the first molecular evidence for the presence of interactions between the Moco biosynthetic machinery and an apomolybdoenzyme, the E. coli aponitrate reductase A, being used as a model. Interestingly, two conditions have to be satisfied to permit any of the interactions to occur, the presence of a mature and active Moco and the presence of the NarJ chaperone. Taken together, our data point to an unexpected essential role for the enzyme-specific chaperones by NarJ in the interaction between the Moco carrier and the and bacterial and used in this work in as G. A. D. PubMed Google and by as by J.H. A Scholar). of was to the M. J. Bacteriol. PubMed Google Scholar). insertion within was to the S. A. PubMed Scopus Google Scholar) thus forming the in or and final and and used in this or or G. J. A. D. S. A. 1998; PubMed Scopus Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google to of coli G. J. A. D. S. A. 1998; PubMed Scopus Google to of coli G. J. A. D. S. A. 1998; PubMed Scopus Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google NarJ E. coli in a new for the of and and by using of as and into the of the to a by and This was and into the of the For the of the and with allowing further of a The was and into the In these three or with the gene the of the G. J. A. D. S. A. 1998; PubMed Scopus Google Scholar). interactions have been using a bacterial two-hybrid on of activity as (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar, G. J. A. D. S. A. 1998; PubMed Scopus Google Scholar). interactions by activity in in with as (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). The activity in the of three and by the between Mo and NarG the in interaction among Mo proteins involved in the final stages of Moco biosynthesis (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) also be involved in its incorporation within resident interactions between these Mo proteins and the aponitrate reductase as a by a bacterial two-hybrid G. J. A. D. S. A. 1998; PubMed Scopus Google Scholar). In an interactions between the subunit, and of the four Mo proteins (MogA, MoeA, MobA, and MobB) in a Interestingly, of the four proteins to with MoeA, and the of interaction several interactions between Mo proteins have been shown to require binding of Moco intermediates (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google has been the presence of Moco is also needed for interaction with the of Moco on the interactions has been in a and of the interactions have been the that NarG not with of the Mo proteins but with a Mo protein complex in such one have the of some of the interactions in the that of the Mo proteins and with the such a the of several mutations Moco biosynthesis stages and on the interaction among the four Mo proteins (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) has been The interactions between NarG and of the four Mo proteins have been in a an active Moco for enzymes 1). of the Mo proteins with NarG Such an observation be the of the of the active Moco for enzymes such as nitrate reductase A, the of of a Mo protein complex of the of MobA and in such a the presence of or proteins and not of to a of the (12Palmer T. Santini C.L. Iobbi-Nivol C. Eaves D.J. Boxer D.H. Giordano G. Mol. Microbiol. 1996; 20: 875-884Crossref PubMed Scopus (151) Google Scholar, A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) and as a be the interaction between and NarG has been Interestingly, interaction has been the to the of MobA as a of a Mo protein the only complex to with NarG and one which not form in a a interactions have been in a Interestingly, MogA, MoeA, and MobA with NarG as in the but a not the of the in a (12Palmer T. Santini C.L. Iobbi-Nivol C. Eaves D.J. Boxer D.H. Giordano G. Mol. Microbiol. 1996; 20: 875-884Crossref PubMed Scopus (151) Google the of Mo proteins required for the interaction with NarG is MogA, MoeA, and MPT in a on the Met. Ions. Biol. Syst. 2002; 39: Google Scholar) is to or interactions among the Mo proteins (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). such a which a Moco and the of the Mo proteins has been to the interactions between NarG and of the Mo proteins. Interestingly, all of the interactions that the presence of a mature Moco is a for interactions between the Mo proteins and of a between NarG and the Mo is a of molybdenum and has been shown to be into the Moco biosynthetic a In E. coli, the of to the of a to the synthesis of molybdoenzymes (17Amy N.K. Rajagopalan K.V. J. Bacteriol. 1979; 140: 114-124Crossref PubMed Google Scholar, R.A. Magalon A. Giordano G. Guigliarelli B. Blasco F. Weiner J.H. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar) with the exception of the trimethylamine-N-oxide reductase J. Santini C.L. M. Giordano G. Mol. Microbiol. PubMed Scopus Google Scholar). In this only a of the has the cofactor J. Santini C.L. M. Giordano G. Mol. Microbiol. PubMed Scopus Google Scholar). prevents molybdenum by MPT and insertion of the of the cofactor into the nitrate reductase A as by the structure of the R.A. Magalon A. Giordano G. Guigliarelli B. Blasco F. Weiner J.H. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar, R.A. M.G. Palak M. Blasco F. Strynadka N.C. Weiner J.H. 2004; PubMed Scopus Google Scholar). the of the of cofactor within the E. coli nitrate reductase A, interactions have been in a by It is to that the interaction among Mo proteins is these conditions as (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). NarG with NarJ not any with of the Mo proteins thus the of Taken together, all of these results strongly that interactions between NarG and the Mo proteins require mature and active Moco i.e. Mo-(bis-MGD) between Mo and NarG further NarJ and Moco incorporation within the aponitrate reductase A strictly requires the presence of the enzyme-specific chaperone NarJ (13Blasco F. Dos Santos J.P. Magalon A. Frixon C. Guigliarelli B. Santini C.L. Giordano G. Mol. Microbiol. 1998; 28: 435-447Crossref PubMed Scopus (118) Google Scholar, F. Pommier J. V. M. Giordano G. Mol. Microbiol. 1992; PubMed Scopus Google one can envision that this protein is needed for the interactions between NarG and the Mo proteins. the of the NarJ an of has been in a of the the Interestingly, all of the interactions have been a critical role for NarJ not this a allowing the of NarJ with the protein has been The presence of NarJ the interactions between NarG and the Mo proteins to an unexpected role for NarJ in the Moco incorporation process. among the proteins and F. C. Giordano G. M. V. Mol. PubMed Scopus Google Scholar) NarJ is the only protein required to allow NarG to with the Mo a has been by all of the interactions have been to the NarJ However, NarJ in not allow a of the interactions between NarG and the Mo proteins to a role for the structural partner in such a a a allowing of with have been and not the interactions of NarG with the Mo proteins. of and NarJ with was required to the interactions Such a that of the NarG for interaction with of the Mo proteins can only be by the of its partner structural subunit, and of the NarJ chaperone. have the to their to by enzymes and their E. coli several molybdoenzymes all of which as terminal enzymes in the D.J. Microbiology. PubMed Scopus Google Scholar). of active molybdoenzymes on the of synthesis with synthesis and of the molybdenum mature and active Moco is synthesized within the various resident apomolybdoenzymes and incorporate Moco a which in some involves enzyme-specific chaperones. The present work has several for the Moco incorporation process. to our (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google a complex made up by MogA, MoeA, and MobA exist allowing between the two steps of Moco biosynthesis i.e. molybdenum and nucleotide binding to active Moco, although the the interactions among the Mo proteins involved in the final stages of Moco biosynthesis to its subsequent incorporation into various In this using a bacterial two-hybrid we have the interaction of an by the of the E. coli nitrate reductase A and four Mo proteins (MogA, MoeA, MobA, and It is to that one have an interaction of NarG with a Mo i.e. MobA, of its role in a of Moco biosynthesis with several Mo proteins. Interestingly, all of the interactions with NarG in the of Moco a situation in a our have shown that interaction was until of the Moco in with the interactions among the Mo proteins (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). these the that NarG with a protein complex in the presence of Moco as (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) with proteins. Such a has for the of the Moco incorporation mechanism as a transfer of mature Moco the Mo protein complex onto the apomolybdoenzymes. a Mo protein complex could the Moco carrier allowing the protection and transfer of active and mature Moco onto resident apomolybdoenzymes as in our work (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). of the role of the NarJ chaperone for Moco incorporation within the E. coli aponitrate reductase A (13Blasco F. Dos Santos J.P. Magalon A. Frixon C. Guigliarelli B. Santini C.L. Giordano G. Mol. Microbiol. 1998; 28: 435-447Crossref PubMed Scopus (118) Google has been to or not the of NarJ have an on the interactions between of the Mo proteins and NarJ plays an essential role in allowing interactions between NarG and the Mo protein the the Moco delivery the chaperone with of the Mo to this further a of the NarJ-assisted Moco incorporation process, has been the of interactions between NarG and the Mo proteins can also exist in the of the structural partner i.e. Moco is within NarG its with the of the nitrate reductase Our results have that the interactions between NarG and of the Mo proteins can only occur and NarJ a mature Moco only be onto an the of the of the complex R.A. M.G. Palak M. Blasco F. Strynadka N.C. Weiner J.H. 2004; PubMed Scopus Google is to of the Mo-(bis-MGD) cofactor can be within such a NarJ have to such a complex i.e. the In work has that only the complex is to with NarJ and as such to incorporate G. Giordano, and A. Magalon, in of the complex to the maturation process be a Moco biosynthesis and incorporation within a the E. coli nitrate reductase A can be our work (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) and the present results The that (i) the interaction between NarG and its NarJ chaperone is an as such interaction is in any mo not (ii) the final stages of Moco biosynthesis occur on a protein complex made up of MogA, MoeA, and MobA (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) of the and (iii) the interaction between the Mo protein complex and the aponitrate reductase only the of Moco biosynthesis and in the presence of the NarJ chaperone. a to has been shown to be as such into the Moco biosynthesis a mechanism most of the E. coli molybdoenzymes For in to the trimethylamine-N-oxide reductase J. Santini C.L. M. Giordano G. Mol. Microbiol. PubMed Scopus Google nitrate reductase A incorporate a tungsten-substituted cofactor as by the structure of the complex R.A. M.G. Palak M. Blasco F. Strynadka N.C. Weiner J.H. 2004; PubMed Scopus Google Scholar). Such an observation the the interactions between NarG and of the four Mo proteins be in the presence of In of the interactions was an to the of cofactor within the aponitrate reductase A. One that of some interactions among the Mo proteins has been these conditions (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). the of the Mo protein complex to to such as the nitrate reductase to its of the essential role of NarJ for these interactions and not of TorD as shown by the of of a (14Pommier J. Mejean V. Giordano G. Iobbi-Nivol C. J. Biol. Chem. 1998; 273: 16615-16620Abstract Full Text Full Text PDF PubMed Scopus (116) Google is to that such enzyme-specific chaperones ensure the and the of the Moco incorporation process. to such a incorporation of within the E. coli trimethylamine-N-oxide reductase be the of the of the TorD chaperone. In the present a of protein-protein interactions among and between the Mo proteins and an thus forming most a large and However, visualization be by the of the complex made between the Mo proteins and as as conditions required for its formation to that to an Moco transfer and of the to the molecular by several have been not Such or and in to the of the a and mechanism for molybdoenzymes It is to that the to in an active form or enzymes in E. coli has been for a S. Rajagopalan K.V. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar, Rajagopalan K.V. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, Weiner J.H. J. Bacteriol. PubMed Google Scholar, J.C. Rajagopalan K.V. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus (54) Google Scholar). to such the Moco biosynthetic and delivery machinery is to to a in mature In the of the nitrate reductase A, the Moco biosynthesis with synthesis the of A. Shanmugam K.T. Arch. Microbiol. PubMed Scopus Google Scholar). the is C. T. Whitty P.W. E. Boxer D.H. Microbiology. 1995; PubMed Scopus Google Scholar). has also that gene is that the of Mo proteins allowing the final stages of Moco biosynthesis and incorporation of Mo-(bis-MGD) cofactor within the aponitrate reductase A of MogA, MoeA, and MobA, is to that MoeA is the only protein of which as the proteins involved in the final stages of Moco biosynthesis also in charge of Moco delivery in several the process to be to allow of the Mo proteins in the The function of the enzyme-specific chaperones as such, to the Moco incorporation process. In the of the nitrate reductase A, the NarJ chaperone is strictly required to allow Moco transfer (12Palmer T. Santini C.L. Iobbi-Nivol C. Eaves D.J. Boxer D.H. Giordano G. Mol. Microbiol. 1996; 20: 875-884Crossref PubMed Scopus (151) Google Scholar, 13Blasco F. Dos Santos J.P. Magalon A. Frixon C. Guigliarelli B. Santini C.L. Giordano G. Mol. Microbiol. 1998; 28: 435-447Crossref PubMed Scopus (118) Google Scholar) the interaction with the Moco biosynthetic machinery the the presence of the TorD chaperone Moco incorporation within the E. coli trimethylamine-N-oxide reductase M. Mejean V. Giudici-Orticoni M.T. Samama J.P. Iobbi-Nivol C. J. Biol. Chem. 2003; 278: 28787-28792Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar). processes the of proteins. such protein-protein interactions an essential In this we several concerning the that Mo proteins work in the steps of Moco biosynthesis (19Magalon A. Frixon C. Pommier J. Giordano G. Blasco F. J. Biol. Chem. 2002; 277: 48199-48204Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) and transfer the active Moco to the aponitrate which as a to the protein Moco can thus be as a to (i) of Moco (ii) the of MogA, MoeA, and MobA, (iii) and between for such as A of our was that the NarJ chaperone is needed to allow the Mo proteins to with We J. Weiner the for of for
Vergnes et al. (Sat,) studied this question.
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