DUAL ROLE OF THE ESCHERICHIA COLI MetE PROTEIN – METHIONINE BIOSYNTHESIS AND STRESS PROTECTION

Survival in a wide range of environmental stress conditions is a challenge for bacteria. Previous experiments indicated that the amino acid methionine confers sensitivity to several types of environmental stresses in Escherichia coli. Here we show that MetE, the last enzyme of the methionine biosynthesis, confers a higher survival to high temperature, oxidative and low pH stress. The results show that when the bacteria are exposed to these stresses, their survival depends on the abundance of MetE in the cell. MetE is one of the most abundant proteins in the cell (3-5% of all proteins in the cell), probably because it has a role in stress protection.