Cloning, molecular analysis and insertional mutagenesis of the bidirectional hydrogenase genes from the cyanobacterium Anacystis nidulans

摘要: Among cyanobacteria, the heterocystous, N2-fixing Anabaena variabilis and unicellular Anacystis nidulans have recently been shown to possess an NAD+-dependent, bidirectional hydrogenase. A 5.0 kb DNA segment of A. genome is now identified harbor structural genes hoxUYH coding for three subunits The gene arrangement in remarkably dissimilar. In nidulans, but not variabilis, four accessory hoxW, hypA, hypB hypF could be downstream hoxH. An insertional homozygous mutant hoxH from was completely inactive performing Na2S204-dependent H2 evolution utilize gas with almost 50% activity wild type. These findings first defined hydrogenase any photosynthetic, 02-evolving microorganism indicate that cyanobacterium possesses both uptake a physiological role(s) two hydrogenases non-N2-fixing cyanobacteria yet understood.