The sypA, sypB, and sypC Synthetase Genes Encode Twenty-Two Modules Involved in the Nonribosomal Peptide Synthesis of Syringopeptin by Pseudomonas syringae pv. syringae B301D

Abstract

Syringopeptin is a necrosis-inducing phytotoxin, composed of 22 amino acids attached to a 3-hydroxy fatty acid tail. Syringopeptin, produced by Pseudomonas syringae pv. syringae, functions as a virulence determinant in the plant-pathogen interaction. A 73,800-bp DNA region was sequenced, and analysis identified three large open reading frames, sypA, sypB, and sypC, that are 16.1, 16.3, and 40.6 kb in size. Sequence analysis of the putative SypA, SypB, and SypC sequences determined that they are homologous to peptide synthetases, containing five, five, and twelve amino acid activation modules, respectively. Each module exhibited characteristic domains for condensation, aminoacyl adenylation, and thiolation. Within the aminoacyl adenylation domain is a region responsible for substrate specificity. Phylogenetic analysis of the substrate-binding pockets resulted in clustering of the 22 syringopeptin modules into nine groups. This clustering reflects the substrate amino acids predicted to be recognized by each of the respective modules based on placement of the syringopeptin NRPS (nonribosomal peptide synthetase) system in the linear (type A) group. Finally, SypC contains two C-terminal thioesterase domains predicted to catalyze the release of syringopeptin from the synthetase and peptide cyclization to form the lactone ring. The syringopeptin synthetases, which carry 22 NRPS modules, represent the largest linear NRPS system described for a prokaryote.

Genetic and functional characterization of the gene cluster directing the biosynthesis of putisolvin I and II in Pseudomonas putida strain PCL1445

“…This is similar to previous studies on syringopeptin (Scholz-Schroeder et al, 2003), arthrofactin (Roongsawang et al, 2003), and the predicted lipodecapeptide of strain Pf-5 (Paulsen et al, 2005) in which no internal E-domains were found. This observation suggests the presence of an external racemase, which recently was further supported by the discovery of specific sequence motifs in the T-domains of the arf synthetic template (Roongsawang et al, 2003).…”

“…The genes encoding multimodular nonribosomal peptide synthetases (NRPSs) for syringomycin and syringopeptin (Kleinkauf & von Döhren, 1996;Guenzi et al, 1998;Scholz-Schroeder et al, 2003) of P. syringae pv. syringae B301D and arthrofactin of Pseudomonas sp.…”

Characterization of the Transcriptional Activators SalA and SyrF, Which Are Required for Syringomycin and Syringopeptin Production byPseudomonas syringaepv. syringae

“…syringae is coordinately controlled by a common regulatory mechanism. Both toxins are lipodepsipeptides and are synthesized separately by modular nonribosomal peptide synthetases (24,62,72). Genes dedicated to the biosynthesis, secretion, and regulation of the two toxins are localized in the syringomycin (syr) and syringopeptin (syp) gene clusters, which are adjacent to one another on the chromosome (40,62).…”

“…Both toxins are lipodepsipeptides and are synthesized separately by modular nonribosomal peptide synthetases (24,62,72). Genes dedicated to the biosynthesis, secretion, and regulation of the two toxins are localized in the syringomycin (syr) and syringopeptin (syp) gene clusters, which are adjacent to one another on the chromosome (40,62). Assembly of the two compounds is induced by plant signal molecules such as arbutin and D-fructose (48,68).…”

Functional Analysis of A Pyoverdine Synthetase fromPseudomonassp. MIS38

“…lack a conventional E-domain, but the product peptide contains D-form amino acid residues. 6,7) Such is the case for arthrofactin synthetase (ArfA/B/C). 5) When the primary structures of the Cdomains of L-peptidyl donors and D-peptidyl donors were compared, it was found that they belonged to different lineage.…”