Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

The Heterodisulfide Reductase from Methanobacterium Thermoautotrophicum Contains Sequence Motifs Characteristic of pyridine‐Nucleotide‐Dependent Thioredoxin Reductases

The Heterodisulfide Reductase from Methanobacterium Thermoautotrophicum Contains Sequence Motifs... The genes hdrA, hdrB and hdrC, encoding the three subunits of the iron‐sulfur flavoprotein heterodisulfide reductase, have been cloned and sequenced. HdrA (72.19 kDa) was found to contain a region of amino acid sequence highly similar to the FAD‐binding domain of pyridine‐nucleotide‐dependent disulfide oxidoreductases. Additionally, 110 amino acids C‐terminal to the FAD‐binding consensus, a short polypeptide stretch (VX2CATID) was detected which shows similarity to the region of thioredoxine reductase that contains the active‐site cysteine residues (VX2CATCD). These findings suggest that HdrA harbors the site of heterodisulfide reduction and that the catalytic mechanism of the enzyme is similar to that of pyridine‐nucleotide‐dependent thioredoxin reductase. HdrA was additionally found to contain four copies of the sequence motif CX2CX2CX3C(P), indicating the presence of four [4Fe‐4S] clusters. Two such sequence motifs were also present in HdrC (21.76 kDa), the N‐terminal amino acid sequence of which showed sequence similarity to the γ‐subunit of the anaerobic glycerol‐3‐phosphate dehydrogenase of Escherichia coli. HdrC is therefore considered to be an electron carrier protein that contains two [4Fe‐4S] clusters. HdrB (33.46 kDa) did not show sequence similarity to other known proteins, but appears to possess a C‐terminal hydrophobic α‐helix that might function as a membrane anchor. Although hdrB and hdrC are juxtaposed, these genes are not near hdrA. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Febs Journal Wiley

The Heterodisulfide Reductase from Methanobacterium Thermoautotrophicum Contains Sequence Motifs Characteristic of pyridine‐Nucleotide‐Dependent Thioredoxin Reductases

Download PDF
9 pages

Loading next page...
 
/lp/wiley/the-heterodisulfide-reductase-from-methanobacterium-hcOVFUmLda

References (48)

Publisher
Wiley
Copyright
Copyright © 1994 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1742-464X
eISSN
1742-4658
DOI
10.1111/j.1432-1033.1994.00253.x
Publisher site
See Article on Publisher Site

Abstract

The genes hdrA, hdrB and hdrC, encoding the three subunits of the iron‐sulfur flavoprotein heterodisulfide reductase, have been cloned and sequenced. HdrA (72.19 kDa) was found to contain a region of amino acid sequence highly similar to the FAD‐binding domain of pyridine‐nucleotide‐dependent disulfide oxidoreductases. Additionally, 110 amino acids C‐terminal to the FAD‐binding consensus, a short polypeptide stretch (VX2CATID) was detected which shows similarity to the region of thioredoxine reductase that contains the active‐site cysteine residues (VX2CATCD). These findings suggest that HdrA harbors the site of heterodisulfide reduction and that the catalytic mechanism of the enzyme is similar to that of pyridine‐nucleotide‐dependent thioredoxin reductase. HdrA was additionally found to contain four copies of the sequence motif CX2CX2CX3C(P), indicating the presence of four [4Fe‐4S] clusters. Two such sequence motifs were also present in HdrC (21.76 kDa), the N‐terminal amino acid sequence of which showed sequence similarity to the γ‐subunit of the anaerobic glycerol‐3‐phosphate dehydrogenase of Escherichia coli. HdrC is therefore considered to be an electron carrier protein that contains two [4Fe‐4S] clusters. HdrB (33.46 kDa) did not show sequence similarity to other known proteins, but appears to possess a C‐terminal hydrophobic α‐helix that might function as a membrane anchor. Although hdrB and hdrC are juxtaposed, these genes are not near hdrA.

Journal

The Febs Journal – Wiley

Published: Oct 1, 1994

There are no references for this article.