title: A Ferredoxin Disulfide Reductase Delivers Electrons to the Methanosarcina barkeri Class III Ribonucleotide Reductase.
abstract: Two subtypes of class III anaerobic ribonucleotide reductases (RNRs) studied so far couple the reduction of ribonucleotides to the oxidation of formate, or the oxidation of NADPH via thioredoxin and thioredoxin reductase. Certain methanogenic archaea contain a phylogenetically distinct third subtype of class III RNR, with distinct active-site residues. Here we report the cloning and recombinant expression of the Methanosarcina barkeri class III RNR and show that the electrons required for ribonucleotide reduction can be delivered by a [4Fe-4S] protein ferredoxin disulfide reductase, and a conserved thioredoxin-like protein NrdH present in the RNR operon. The diversity of class III RNRs reflects the diversity of electron carriers used in anaerobic metabolism.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Department of Chemistry, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Divya
authors.initials: D
authors.lastname: Prakash
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: James G
authors.initials: JG
authors.lastname: Ferry
authors.affiliation: Department of Chemistry, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States.
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Elliott
authors.forename: JoAnne
authors.initials: J
authors.lastname: Stubbe
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019343:Citric Acid / Q000378:metabolism; D003001:Cloning, Molecular; D004583:Electrons; D005288:Ferredoxins / Q000378:metabolism; D017021:Methanosarcina barkeri / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000378:metabolism*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012264:Ribonucleotide Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012265:Ribonucleotides / Q000378:metabolism
chemical_list: D005288:Ferredoxins; D011994:Recombinant Proteins; D012265:Ribonucleotides; D019343:Citric Acid; D012264:Ribonucleotide Reductases; C101141:anaerobic ribonucleotide reductase; D050862:Oxidoreductases Acting on Sulfur Group Donors