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Selenate Reductase (selenate + reductase)

Distribution by Scientific Domains
Life Sciences40%

Selected Abstracts

Crystallization and preliminary X-ray analysis of the selenate reductase from Thauera selenatis

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2002
Megan J. Maher
Selenate reductase from Thauera selenatis was crystallized using ammonium sulfate as a precipitant. Crystals of selenate reductase belong to the space group C2, with unit-cell parameters a = 116.9, b = 67.5, c = 186.7,Å, , = 90°. Native data to 2.1,Å resolution have been collected and a heavy-atom derivative has been identified following soaking of the crystals in a solution of trimethyl lead acetate. [source]

Role of menaquinone biosynthesis genes in selenate reduction by Enterobacter cloacae SLD1a-1 and Escherichia coli K12

ENVIRONMENTAL MICROBIOLOGY, Issue 1 2009
Jincai Ma
Summary In this study, we investigated the role of menaquinone biosynthesis genes in selenate reduction by Enterobacter cloacae SLD1a-1 and Escherichia coli K12. A mini-Tn5 transposon mutant of E. cloacae SLD1a-1, designated as 4E6, was isolated that had lost the ability to reduce Se(VI) to Se(0). Genetic analysis of mutant strain 4E6 showed that the transposon was inserted within a menD gene among a menFDHBCE gene cluster that encodes for proteins required for menaquinone biosynthesis. A group of E. coli K12 strains with single mutations in the menF, menD, menC and menE genes were tested for loss of selenate reduction activity. The results showed that E. coli K12 carrying a deletion of either the menD, menC or menE gene was unable to reduce selenate. Complementation using wild-type sequences of the E. cloacae SLD1a-1 menFDHBCE sequence successfully restored the selenate reduction activity in mutant strain 4E6, and E. coli K12 menD and menE mutants. Selenate reduction activity in 4E6 was also restored by chemical complementation using the menaquinone precursor compound 1,4-dihydroxy-2-nathphoic acid. The results of this work suggest that menaquinones are an important source of electrons for the selenate reductase, and are required for selenate reduction activity in E. cloacae SLD1a-1 and E. coli K12. [source]

Crystallization and preliminary X-ray analysis of the selenate reductase from Thauera selenatis

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2002
Megan J. Maher
Selenate reductase from Thauera selenatis was crystallized using ammonium sulfate as a precipitant. Crystals of selenate reductase belong to the space group C2, with unit-cell parameters a = 116.9, b = 67.5, c = 186.7,Å, , = 90°. Native data to 2.1,Å resolution have been collected and a heavy-atom derivative has been identified following soaking of the crystals in a solution of trimethyl lead acetate. [source]

Look on the positive side!

FEMS MICROBIOLOGY LETTERS, Issue 2 2007
Archaeal' membrane-bound nitrate reductases, The orientation, bioenergetics of, identification
Abstract Many species of Bacteria and Archaea respire nitrate using a molybdenum-dependent membrane-bound respiratory system called Nar. Classically, the ,Bacterial' Nar system is oriented such that nitrate reduction takes place on the inside of this membrane. However, the active site subunit of the ,Archaeal' Nar systems has a twin arginine (,RR') motif, which is a suggestion of translocation to the outside of the cytoplasmic membrane. These ,Archaeal' type of nitrate reductases are part of a group of molybdoenzymes with an ,RR' motif that are predicted to have an aspartate ligand to the molybdenum ion. This group includes selenate reductases and possible sequence signatures are described that serve to distinguish the Nar nitrate reductases from the selenate reductases. The ,RR' sequences of nitrate reductases of Archaea and some that have recently emerged in Bacteria are also considered and it is concluded that there is good evidence for there being both Archaeal and Bacterial examples of Nar-type nitrate reductases with an active site on the outside of the cytoplasmic membrane. Finally, the bioenergetic consequences of nitrate reduction on the outside of the cytoplasmic membrane have been explored. [source]