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B6db references: 29307827.

type Journal Article
authors Manning ME, Danson EJ, Calderone CT
title Functional chararacterization of the enzymes TabB and TabD involved in tabtoxin biosynthesis by Pseudomonas syringae
journal Biochem Biophys Res Commun
sel selected
ui 29307827
year (2018)
volume 496
number 1
pages 212-217
keywords Enzyme function; Natural product biosynthesis; Tabtoxin
abstract Pseudomonas syringae pv. tabaci ATCC 11528 produces tabtoxin, a β-lactam- containing dipeptide phytotoxin. Tabtoxinine-β-lactam (TβL), one of tabtoxin's constituent amino acids, structurally mimics lysine, and many of the proteins encoded by the tabtoxin biosynthetic gene cluster are homologs of lysine biosynthetic enzymes, suggesting that the tabtoxin and lysine biosynthetic routes parallel one another. We cloned and expressed TabB and TabD, predicted homologs of tetrahydrodipicolinate (THDPA)-N-acyltransferase and N-acyl-THDPA aminotransferase, respectively, to determine their activities in vitro. We confirmed that TabB succinylates THDPA and that TabD is a PLP-dependent aminotransferase that utilizes glutamate as an amine donor. Surprisingly, we also found that though TabD could utilize the TabB product N-succinyl-THDPA as a substrate, THDPA itself was also recognized. These observations reveal that TabB functionally duplicates DapD, the THDPA- N-succinyltransferase involved in lysine biosynthesis, and reinforce the close relationship between the metabolic logics underpinning the respective biosynthetic pathways.

last changed 2018/04/03 14:47

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