Mutational analysis of O-acetylserine (thiol) lyase conducted in yeast two-hybrid system

Cysteine biosynthesis, achieved by the sequential reaction of two enzymes, serine acetyltransferase and O-acetylserine (thiol) lyase (OASTL), represents the final step of sulfur assimilation pathway in plants and bacteria. The two enzymes form a bi-enzymatic cysteine synthase complex through specific protein-protein interactions. To identify the amino acids important for cysteine synthase complex formation, several mutations in bacterial OASTL were designed. Effects of mutagenesis were verified in a yeast two-hybrid model that allowed monitoring both, protein-protein interactions and the enzymatic activity of OASTL.