MOAA OF ARTHROBACTER NICOTINOVORANS PAO1 INVOLVED IN MO-PTERIN COFACTOR SYNTHESIS IS AN FE-S PROTEIN

MoaA, involved in an early step in the biosynthesis of the molybdopter in cofactor (MoCo), has not yet been characterized biochemically and t he reaction it catalyzes is unknown, We overexpressed MoaA from pAO1 o f Arthrobacter nicotinovorans in Escherichia coli as a N-terminal fusi on with either glutathione-S-transferase or a 6-histidine tag, The pAO 1 encoded MoaA as well as the fusion proteins functionally complement E. coli moaA mutants, Here we show that purified MoaA contains approxi mately 4 mu M Fe and approximately 3 mu M acid-labile S/mu M protein, EPR spectroscopy revealed a predominant signal at g(av) = 2.01, indica tive of a [3Fe-xS] cluster.