Functional chararacterization of the enzymes TabB and TabD involved in tabtoxin biosynthesis by Pseudomonas syringae.

Autor: Manning ME; Department of Chemistry, Carleton College, 1 North College Street, Northfield, MN 55057, United States., Danson EJ; Department of Chemistry, Carleton College, 1 North College Street, Northfield, MN 55057, United States., Calderone CT; Department of Chemistry, Carleton College, 1 North College Street, Northfield, MN 55057, United States. Electronic address: ccalderone@carleton.edu.
Jazyk: angličtina
Zdroj: Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2018 Jan 29; Vol. 496 (1), pp. 212-217. Date of Electronic Publication: 2018 Jan 04.
DOI: 10.1016/j.bbrc.2018.01.028
Abstrakt: 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.
(Copyright © 2018 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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