title: Binary reducing equivalent pathways using NADPH-thioredoxin reductase and ferredoxin-thioredoxin reductase in the cyanobacterium Synechocystis sp. strain PCC 6803.
abstract: Thioredoxin (Trx) is a small ubiquitous protein involved in the disulfide-dithiol exchange reaction occurring in cells and organelles. In vivo, Trx is reduced by Trx reductase using NADPH or photosynthetically produced reducing equivalents, and the reduced form Trx takes on the physiological functions. In the cyanobacterium Synechocystis sp. PCC6803, two Trx reductases, ferredoxin-Trx reductase (FTR) and NADPH-Trx reductase (NTR), and four typical Trx isoforms have been identified by genomic analysis. Based on analysis of the physiological features of the Trx reductase disruptants, we found that the NTR-Trx pathway is important for the antioxidant system, whereas the FTR-Trx pathway may play a more important role in the control of cell growth rate. In addition, by quantification of Trx abundance in the wild-type and the disruptant Synechocystis cells, we found that the gene product of slr0623, the homolog of m-type Trx in higher plants, is the most abundant Trx, and that accumulation of Trx isoforms occurs dependent on the expression of the other redox-related proteins. A study of the binary reducing equivalent pathways in cyanobacterial cells is reported here.
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, 226-8503 Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Hishiya
authors.forename: Wakako
authors.initials: W
authors.lastname: Hatakeyama
authors.forename: Yoko
authors.initials: Y
authors.lastname: Mizota
authors.forename: Naomi
authors.initials: N
authors.lastname: Hosoya-Matsuda
authors.forename: Ken
authors.initials: K
authors.lastname: Motohashi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikeuchi
authors.forename: Toru
authors.initials: T
authors.lastname: Hisabori
mesh_terms: D015964:Gene Expression Regulation, Bacterial; D007506:Iron-Sulfur Proteins / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms; D046939:Synechocystis / Q000201:enzymology* / Q000235:genetics; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics* / Q000378:metabolism*; D013997:Time Factors
chemical_list: D007506:Iron-Sulfur Proteins; D020033:Protein Isoforms; D010088:Oxidoreductases; C021588:ferredoxin-thioredoxin reductase; D013880:Thioredoxin-Disulfide Reductase