Studies of the domain structure of mammalian DNA polymerase β. Identification of a discrete template binding domain

A. Kumar, Steven Widen, K. R. Williams, P. Kedar, R. L. Karpel, S. H. Wilson

Research output: Contribution to journalArticlepeer-review

157 Scopus citations

Abstract

Characterization of the domain structure of DNA polymerase β is reported. Large scale overproduction of the rat protein in coli was achieved, and the purified recombinant protein was verified by sequencing tryptic peptides. This protein is both a single-stranded DNA binding protein and a DNA polymerase consisting of one polypeptide chain of 334 amino acids. As revealed by controlled proteolysis experiments, the protein is organized in two relatively protease-resistant segments linked by a short protease-sensitive region. One of these protease-resistant segments represents the NH2-terminal 20% of the protein. This NH2-terminal domain (of about 75 residues) has strong affinity for single-stranded nucleic acids. The other protease-resistant segment, representing the COOH-terminal domain of ~ 250 residues, does not bind to nucleic acids. Neither domain, tested as purified proteins, has substantial DNA polymerase activity. The results suggest that the NH2-terminal domain is principally responsible for the template binding activity of the intact protein.

Original languageEnglish (US)
Pages (from-to)2124-2131
Number of pages8
JournalJournal of Biological Chemistry
Volume265
Issue number4
StatePublished - Aug 29 1990
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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