Characterization Of Two Redundant Aspergillus flavus Peptide Synthetase8208;like Enzymes

Daniel Schwenk, Saori Amaike, Ry Forseth, Frank Schroeder, Nancy Keller, Dirk Hoffmeister

Author address: 

Hans-Knöll-Institut Jena   University of Wisconsin, Madison, WI   Cornell University, Ithaca, NY Friedrich-Schiller-Universität Jena

Abstract: 

LaeA, a regulator of secondary metabolism in fungi, controls expression of two genes encoding NRPS8208;like enzymes in Aspergillus flavus, termed LnaA and LnbA. Although these enzymes resemble α 8208;aminoadipate reductases (i.e., primary metabolism enzymes), gene deletion and knockdown experiments pointed to a role for LnaA and LnbA in secondary metabolism. Specifically, the biosyntheses of heterocyclic L8208;tyrosine8208;derived natural products are dependent on these enzymes. Genetic data is also suggestive of functional redundancy of these two enzymes. Hexahistidine8208;tagged LnaA and LnbA were heterologously produced, and assayed using the amino acid8208;dependent ATP8208;pyrophosphate exchange method.  L8208;tyrosine was identified as clearly preferred substrate of both enzymes. Further biochemical characterization established divergent temperature and pH8208;optima, and differences regarding stereospecificity. Our biochemical experiments prove that the LnaA and LnbA substrate spectrum is compatible with their tentative heterocyclic products. Further, participation of α 8208;aminoadipate reductase8208;like NRPSs in secondary metabolism and functional redundancy of LnaA and LnbA, anticipated by genetic methods, is supported by the substrate spectrum of these enzymes.
2012

abstract No: 

PR8.39

Full conference title: 

11 th European Conference on Fungal Genetics
    • ECFG 11th (2012)