The C-terminal zinc finger of the catalytic subunit of DNA polymerase delta is responsible for direct interaction with the B-subunit.

DNA polymerase delta (Pol delta) plays a central role in eukaryotic chromosomal DNA replication, repair and recombination. In fission yeast, Pol delta is a tetrameric enzyme, comprising the catalytic subunit Pol3 and three smaller subunits, Cdc1, Cdc27 and Cdm1. Previous studies have demonstrated a direct interaction between Pol3 and Cdc1, ...
the B-subunit of the complex. Here it is shown that removal of the tandem zinc finger modules located at the C-terminus of Pol3 by targeted proteolysis renders the Pol3 protein non-functional in vivo, and that the C-terminal zinc finger module ZnF2 is both necessary and sufficient for binding to the B-subunit in vivo and in vitro. Extensive mutagenesis of the ZnF2 module identifies important residues for B-subunit binding. In particular, disruption of the ZnF2 module by substitution of the putative metal-coordinating cysteines with alanine abolishes B-subunit binding and in vivo function. Finally, evidence is presented suggesting that the ZnF region is post-translationally modified in fission yeast cells.
Mesh Terms:
Amino Acid Sequence, Catalytic Domain, Cell Cycle Proteins, DNA Polymerase III, Fungal Proteins, Molecular Sequence Data, Mutation, Protein Binding, Protein Subunits, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Two-Hybrid System Techniques, Zinc Fingers
Nucleic Acids Res.
Date: Jun. 03, 2004
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