Structure of rat DNA polymerase beta revealed by partial amino acid sequencing and cDNA cloning

Proc Natl Acad Sci U S A. 1986 Jul;83(14):5106-10. doi: 10.1073/pnas.83.14.5106.


A cDNA library of newborn rat brain poly(A)+ RNA in phage lambda gt11 was screened with a polyclonal antibody against chicken DNA polymerase beta. One positive phage was isolated and purified after testing 2 X 10(7) recombinants. This phage, designated lambda pol beta-10, contained an 1197-base-pair cDNA insert that corresponded to a mRNA with a poly(A) sequence at the 3' terminus and a single, long open-reading frame of 957 bases. The open-reading frame, starting 44 residues from the 5' end of the cDNA, predicted a 36,375-Da protein of 318 amino acids. Comparison of this deduced amino acid sequence with the partial sequence obtained with purified polymerase beta revealed a match of six tryptic peptides, involving a total of 47 amino acid residues. This confirmed the identity of the cDNA. Blot-hybridization analysis of newborn rat brain poly(A)+ RNA revealed a mRNA species of approximately the same size as the cDNA insert; in addition, a second mRNA species approximately equal to 4000 bases long was detected. Computer-derived secondary structure analysis of the enzyme predicted seven regions of alpha-helix distributed throughout and three regions of beta-sheet.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chickens / genetics
  • Cloning, Molecular
  • DNA / analysis
  • DNA Polymerase I / genetics*
  • Poly A / genetics
  • Protein Conformation
  • RNA, Messenger / genetics
  • Rats
  • Sequence Homology, Nucleic Acid


  • RNA, Messenger
  • Poly A
  • DNA
  • DNA Polymerase I

Associated data

  • GENBANK/M13961