4h2s
From Proteopedia
Crystal structure of Bradyrhizobium japonicum glycine:[carrier protein] ligase complexed with cognate carrier protein and AMP
Structural highlights
FunctionAACL1_BRADU Catalyzes the ATP-dependent activation of L-glycine and its transfer to the phosphopantetheine prosthetic group covalently attached to the vicinal carrier protein bsr0959 of yet unknown function. May participate in nonribosomal peptide synthesis or related processes. L-alanine is a poor substrate whereas L-serine or D-amino acids are not substrates for ATP-dependent activation. Does not display tRNA aminoacylation activity.[1] Publication Abstract from PubMedAmino acid:[carrier protein] ligases (aa:CP ligases) are recently discovered enzymes that are highly similar to class II aminoacyl-tRNA synthetases (aaRSs). However, while aaRSs aminoacylate tRNA and supply building blocks for ribosomal translation, aa:CP ligases transfer activated amino acids to the phosphopantetheine group of small carrier proteins. We have solved the crystal structure of an aa:CP ligase complexed with the carrier protein (CP). The CP prosthetic group enters the active site from a different direction than tRNA in class II aaRS complexes through an idiosyncratic tunnel. CP binds to aa:CP ligase in a fundamentally different manner compared to tRNA binding by structurally closely related aaRSs. Based on crystallographic analysis, an enzyme of altered CP specificity was designed, and the mechanism of amino acid transfer to the prosthetic group was proposed. The presented study reveals how a conserved class II aaRS catalytic core can adapt to another function through minor structural alterations. Adaptation of Aminoacyl-tRNA Synthetase Catalytic Core to Carrier Protein Aminoacylation.,Mocibob M, Ivic N, Luic M, Weygand-Durasevic I Structure. 2013 Mar 26. pii: S0969-2126(13)00058-0. doi:, 10.1016/j.str.2013.02.017. PMID:23541895[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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