Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl‐tRNA synthetase do not favour its in vivo inhibition by ochratoxin A

FEBS Letters

Eriani, G.¹  Roth, A.¹  Dirheimer, G.¹  Gangloff, J.¹ 

[1] Institut de Biologie Moléculaire et Cellulaire du CNRS, 15, rue René Descartes, 67084 Strasbourg cédex, France

关键词: Ochratoxin A;    Phenylalanyl-tRNA synthetase;    Bacillus subtilis;    Growth inhibition;   

DOI  :  10.1016/0014-5793(93)81767-T

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ochratoxine A (OTA) inhibits growth of Bacillus subtilis at pHs below 7. Since OTA is a phenylalanine analogue, this effect could be due to inhibition of phenylalanine-tRNA synthetase (PheRS) by competition of this mycotoxin with the amino acid. Homogeneous PheRS was purified from Bacillus subtilis and from E. coli transformed with the PheRS gene. The latter produced about 40 times more PheRS than B. subtilis. The K_m and K_i values of PheRS, respectively, for phenylalanine and OTA were measured and their concentrations within the cell determined. It appears that the concentration of OTA in the cell, in spite of a 25-fold accumulation, remained too low to significantly compete with phenylalanine. This does not suggest PheRS to be the target of OTA in cell growth and protein synthesis inhibition in Bacillus subtilis. It was also shown that the 2–3-fold increase of PheRS in OTA-treated cells is not due to phenylalanine-controlled attenuation regulation.

【 授权许可】

Unknown