|
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 |
Activity |
2.6.1.17 |
Family |
2.6.1.17 |
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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