Suppression of an ilvA mutation in Bacillus subtilis

Abstract

Bacillus subtilis W23 mutant strain MCB326 was temperature sensitive and inhibited by valine. Valine inhibition of growth was specifically reversed by leucine or α-keto-isocaproate. Either leucine or isoleucine overcame the temperature sensitivity. Formation of several isoleucine and valine biosynthetic enzymes was altered in the mutant. MCB326 contained a lesion in the structural gene specifying threonine deaminase and a second mutation which suppressed the isoleucine auxotrophy.