Zinc-bundle structure of the essential RNA polymerase subunit RPB10 from Methanobacterium thermoautotrophicum.
The RNA polymerase subunit RPB10 displays a high level of conservation across archaea and eukarya and is required for cell viability in yeast. Structure determination of this RNA polymerase subunit from Methanobacterium thermoautotrophicum reveals a topology, which we term a zinc-bundle, consisting of three alpha-helices stabilized by a zinc ion. The metal ion is bound within an atypical CX(2)CX(n)CC sequence motif and serves to bridge an N-terminal loop with helix 3. This represents an example of two adjacent zinc-binding Cys residues within an alpha-helix conformation. Conserved surface features of RPB10 include discrete regions of neutral, acidic, and basic residues, the latter being located around the zinc-binding site. One or more of these regions may contribute to the role of this subunit as a scaffold protein within the polymerase holoenzyme.
Mackereth
C D
CD
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3.
Arrowsmith
C H
CH
Edwards
A M
AM
McIntosh
L P
LP
D000595:Amino Acid Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D017014:Methanobacterium / Q000201:enzymology*; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012313:RNA / Q000378:metabolism; D015032:Zinc / Q000737:chemistry*
D012313:RNA; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D015032:Zinc