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 language | English (US) |
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Pages (from-to) | 2124-2131 |
Number of pages | 8 |
Journal | Journal of Biological Chemistry |
Volume | 265 |
Issue number | 4 |
State | Published - 1990 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology