title: Long-chain N-acyl amino acid synthases are linked to the putative PEP-CTERM/exosortase protein-sorting system in Gram-negative bacteria.
abstract: Clones that encode the biosynthesis of long-chain N-acyl amino acids are frequently recovered from activity-based screens of soil metagenomic libraries. Members of a diverse set of enzymes referred to as N-acyl amino acid synthases are responsible for the production of all metagenome-derived N-acyl amino acids characterized to date. Based on the frequency at which N-acyl amino acid synthase genes have been identified from metagenomic samples, related genes are expected to be common throughout the global bacterial metagenome. Homologs of metagenome-derived N-acyl amino acid synthase genes are scarce, however, within the sequenced genomes of cultured bacterial species. Toward the goal of understanding the role(s) played by N-acyl amino acids in environmental bacteria, we looked for conserved genetic features that are positionally linked to metagenome-derived N-acyl amino acid synthase genes. This analysis revealed that N-acyl amino acid synthase genes are frequently found adjacent to genes predicted to encode PEP-CTERM motif-containing proteins and, in some cases, other conserved elements of the PEP-CTERM/exosortase system. Although relatively little is known about the PEP-CTERM/exosortase system, its core components are believed to represent the putative Gram-negative equivalent of the LPXTG/sortase protein-sorting system of Gram-positive bacteria. During the course of this investigation, we were able to provide evidence that an uncharacterized family of hypothetical acyltransferases, which had previously been linked to the PEP-CTERM/exosortase system by bioinformatics, is a new family of N-acyl amino acid synthases that is widely distributed among the PEP-CTERM/exosortase system-containing Proteobacteria.
authors.affiliation: Laboratory of Genetically Encoded Small Molecules, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Craig
authors.forename: Marisa A
authors.initials: MA
authors.lastname: Cherry
authors.forename: Sean F
authors.initials: SF
authors.lastname: Brady
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000096:biosynthesis* / Q000737:chemistry; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019881:Aminoacyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D054892:Metagenome; D008969:Molecular Sequence Data; D010802:Phylogeny; D021381:Protein Transport; D012988:Soil Microbiology
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D019881:Aminoacyltransferases; D000604:Amino Acyl-tRNA Synthetases