Practice question

Structural region trpEDCBA spans approximately seven kilobases encoding catalytic subunits for chorismate to L-tryptophan conversion. trpE and trpD together encode anthranilate synthase component I and component II catalyzing chorismate amination with glutamine; trpD also provides anthranilate phosphoribosyltransferase activity; trpC encodes bifunctional protein with N-terminal indole-3-glycerol phosphate synthase and C-terminal isomerase; trpB and trpA form heterotetrameric tryptophan synthase alpha2beta2 complex converting indole-glycerol phosphate plus serine to tryptophan. Polycistronic arrangement from single promoter ensures coordinated equimolar synthesis of sequential pathway enzymes from one messenger RNA for efficient metabolic flux.