MetW regulates the enzymatic activity of MetX in Pseudomonas

Biosci Biotechnol Biochem. 2021 Feb 18;85(2):351-358. doi: 10.1093/bbb/zbaa044.


Methionine is a canonical amino acid. The protein MetX is a homoserine O-acyltransferase utilized in the methionine biosynthetic pathway. The metW gene is found adjacent to the metX gene in some bacteria, but its functions are unclear. In this study, I focused on the function of MetW and MetX from Pseudomonas aeruginosa (PaMetW and PaMetX). I demonstrated that PaMetW interacted with and activated the homoserine O-succinyltransferase (HST) activity of PaMetX. Furthermore, I elucidated that the HST activity of PaMetX in complex with PaMetW was inhibited by the addition of S-adenosyl-l-homocysteine (SAH), although PaMetX alone showed no feedback inhibition. Since PaMetW possesses a glycine-rich sequence annotated as a SAM/SAH binding site, I also investigated the relationship between this glycine-rich sequence and the inhibition caused by SAH. I revealed that alanine mutation of PaMetW Gly24 reduced the inhibitory effect of SAH. These results suggest that MetW is a regulatory protein of MetX.

Keywords: Pseudomonas aeruginosa; MetW; MetX; feedback inhibition; methionine biosynthesis.

MeSH terms

  • Acetyltransferases / antagonists & inhibitors
  • Acetyltransferases / chemistry
  • Acetyltransferases / metabolism*
  • Amino Acid Sequence
  • Binding Sites
  • Methionine / metabolism
  • Pseudomonas aeruginosa / enzymology*
  • S-Adenosylmethionine / pharmacology


  • S-Adenosylmethionine
  • Methionine
  • Acetyltransferases