GSBS Student Publications


DNA polymerase III of Gram-positive eubacteria is a zinc metalloprotein conserving an essential finger-like domain

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences



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Medical Subject Headings

Amino Acid Sequence; Bacillus subtilis; Binding Sites; Catalysis; *Conserved Sequence; Cysteine; DNA Polymerase III; Electrons; Gram-Positive Bacteria; Histidine; Iron; Metalloendopeptidases; Methyl Methanesulfonate; Molecular Sequence Data; Point Mutation; Protein Structure, Tertiary; Recombinant Proteins; *Zinc Fingers; Zinc Radioisotopes


Life Sciences | Medicine and Health Sciences


DNA polymerase III (pol III) of Gram-positive eubacteria is a catalytically bifunctional DNA polymerase:3'-5' exonuclease [Low, R. L., Rashbaum, S. A., and Cozzarelli, N. R. (1976) J. Biol.Chem. 251, 1311-1325]. The pol III protein conserves, between its exonuclease and dNTP binding sites, a 35-residue segment of primary structure with the potential to form a zinc finger-like structure [Berg, J. M. (1990) Ann. Rev. Biochem. 19, 405-421]. This paper describes results of experiments which probe the capacity of this segment to bind zinc and the role of this segment in enzyme function. The results of metal and mutational analysis of a model pol III derived from Bacillus subtilis indicate that (i) the Gram-positive pol III is a metalloprotein containing tightly bound zinc in a stoichiometry of 1, (ii) the zinc atom is bound within the 35-residue segment, likely in one of two probable finger-like structures, and (iii) the integrity of the zinc-bound structure is specifically critical to the formation and/or function of the enzyme's polymerase site.

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Citation: Biochemistry. 1998 Nov 3;37(44):15254-60. Link to article on publisher's site

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