Detection of putative Zn(II) binding sites within Escherichia coli RNA polymerase: inconsistency between sequence-based prediction and 65Zn blotting.
The availability of repeating 'Cys' and/or 'His' units in a particular order prompts the prediction of Zn(II) finger motifs in a protein. Escherichia coli RNA polymerase has two tightly bound Zn(II) per molecule of the enzyme as detected by atomic absorption spectroscopy. One Zn(II) was identified to be at the beta subunit, whereas the other putative Zn(II) binding site has recently been predicted to be at the N-terminal half of the beta' subunit, from primary sequence analysis. We show here that the beta' subunit has no ability to bind 65Zn(II). On the other hand, the N-terminal domain of the alpha subunit has strong Zn(II) binding ability with no obvious functional implications.
Centre for Cellular and Molecular Biology, Hyderabad, India.
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Sujatha
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Chatterji
D000595:Amino Acid Sequence; D001665:Binding Sites; D001669:Biochemical Phenomena; D001671:Biochemistry; D003198:Computer Simulation; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology*; D008969:Molecular Sequence Data; D010957:Plasmids; D015032:Zinc / Q000378:metabolism*
D012321:DNA-Directed RNA Polymerases; D015032:Zinc