3h9j | pdb_00003h9j
Crystal structure of E. coli MccB + AMPCPP + SeMeT MccA
Structural highlights
Function[MCCC7_ECOLX] Antibacterial peptide, active against enterobacteria including species of Klebsiella, Salmonella, Shigella, Yersinia and Proteus, and strains of E.coli. Inhibits protein translation by blocking aspartyl-tRNA synthetase function and inhibiting production of aminoacetylated tRNA-Asp.[1] [2] [3] [4] [5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 39-kDa Escherichia coli enzyme MccB catalyses a remarkable posttranslational modification of the MccA heptapeptide during the biosynthesis of microcin C7 (MccC7), a 'Trojan horse' antibiotic. The approximately 260-residue C-terminal region of MccB is homologous to ubiquitin-like protein (UBL) activating enzyme (E1) adenylation domains. Accordingly, MccB-catalysed C-terminal MccA-acyl-adenylation is reminiscent of the E1-catalysed activation reaction. However, unlike E1 substrates, which are UBLs with a C-terminal di-glycine sequence, MccB's substrate, MccA, is a short peptide with an essential C-terminal Asn. Furthermore, after an intramolecular rearrangement of MccA-acyl-adenylate, MccB catalyses a second, unique reaction, producing a stable phosphoramidate-linked analogue of acyl-adenylated aspartic acid. We report six-crystal structures of MccB in apo, substrate-, intermediate-, and inhibitor-bound forms. Structural and kinetic analyses reveal a novel-peptide clamping mechanism for MccB binding to heptapeptide substrates and a dynamic-active site for catalysing dual adenosine triphosphate-consuming reactions. The results provide insight into how a distinctive member of the E1 superfamily carries out two-step activation for generating the peptidyl-antibiotic MccC7. How the MccB bacterial ancestor of ubiquitin E1 initiates biosynthesis of the microcin C7 antibiotic.,Regni CA, Roush RF, Miller DJ, Nourse A, Walsh CT, Schulman BA EMBO J. 2009 Jul 8;28(13):1953-64. Epub 2009 Jun 4. PMID:19494832[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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