title: Amino acid sequence of high-redox-potential ferredoxin (HiPIP) isozymes from the extremely halophilic purple phototrophic bacterium, Ectothiorhodospira halophila.
abstract: The amino acid sequences of high-redox-potential ferredoxin (HiPIP) isozymes from Ectothiorhodospira halophila have been determined. These are: isozyme I, EPRAEDGHAHDYVNEAADPSHGRYQEGQLCENCAFWGEAVQDGWGRCTHPDFDEVLVKAEGWCSVYAPA S, and isozyme II, GLPDGVEDLPKAEDDHAHDYVNDAADTDHARFQEGQLCENCQFWVDYVNGWGYCQHPDFTDVLVRGEGW CSVYAPA. Isozyme II is the major form of HiPIP produced by the bacterium (65-80%) and is the most acidic of the known HiPIPs. The two isozymes are 72% identical to one another and require only a single residue deletion for alignment. Comparison of these HiPIPs with seven previously determined sequences revealed only 27% average identity. Both E. halophila HiPIP isozymes are likely to be functional since their sequences are equally distant from those of other species. The E. halophila HiPIP sequences show that H-bonding patterns recognized in Chromatium vinosum HiPIP are likely to be conserved and therefore cannot explain the unusually low redox potentials which have been reported.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002841:Chromatiaceae / Q000201:enzymology*; D006860:Hydrogen Bonding; D007506:Iron-Sulfur Proteins / Q000032:analysis*; D007527:Isoenzymes / Q000032:analysis*; D008667:Metalloproteins / Q000032:analysis*; D045322:Photosynthetic Reaction Center Complex Proteins
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D007527:Isoenzymes; D008667:Metalloproteins; D045322:Photosynthetic Reaction Center Complex Proteins; C007943:high potential iron-sulfur protein