The Inducible Quinate-Shikimate Catabolic Pathway in Neurospora crassa: Genetic Organization

Department of Biology, Yale University, New Haven, Connecticut o652o, U.S.A. ABSTRACT Summary: In Neurospora crassa the conversion of quinate and shikimate to protocatechuate is catalysed by three inducible enzymes. Previous studies have demonstrated that the qa-1 locus encodes a multimeric regulatory protein which is required for the synthesis of the three catabolic enzymes. The qa-2 locus has been shown to encode catabolic dehydroquinase. This work defines two new classes of mutants. The qa-3 locus is the structural gene for a bifunctional enzyme which catalyses the dehydrogenation of quinate and shikimate. Mutants of the qa-4 class specifically lack 5-dehydroshikimate dehydrase. Alleles of the four different qa mutant classes are tightly clustered and are located to the left of me-7 in L.G. VII. Present address: Biology Department, Brookhaven National Laboratory, Upton, New York 11973, U.S.A.