title: Mapping of the interaction interface of DNA polymerase beta with XRCC1.
abstract: Residues of DNA polymerase beta (beta-Pol) that interact with the DNA repair protein XRCC1 have been determined by NMR chemical shift mapping (CSM) and mutagenesis. 15N/(13)C/(2)H/(1)H,(13)C-methyl(Leu,Ile,Val)-labeled beta-Pol palm-thumb domain was used for assignments of the 1H, 15N, and 13C resonances used for CSM of the palm-thumb on forming the 40 kDa complex with the XRCC1 N-terminal domain (NTD). Large chemical shift changes were observed in the thumb on complexation. 15N relaxation data indicate reduction in high-frequency motion for a thumb loop and three palm turn/loops, which showed concomitant chemical shift changes on complexation. A deltaV303-V306 deletion and an L301R/V303R/V306R triple mutation abolished complex formation due to loss in hydrophobicity. In an updated model, the thumb-loop of beta-Pol contacts an edge/face region of the beta sheet of the XRCC1 NTD, while the beta-Pol palm weakly contacts the alpha2 helix.
authors.affiliation: Department of Biochemistry, University of Connecticut Health Center, Farmington, CT 06030, USA. gryk@neuron.uchc.edu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Gryk
authors.forename: Assen
authors.initials: A
authors.lastname: Marintchev
authors.forename: Mark W
authors.initials: MW
authors.lastname: Maciejewski
authors.forename: Anthony
authors.initials: A
authors.lastname: Robertson
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Wilson
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Mullen
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019951:DNA Polymerase beta / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; D019951:DNA Polymerase beta