TY - JOUR
T1 - Interactions between DNA polymerase β and the major covalent adduct of the carcinogen (+)-anti-benzo[a]pyrene diol epoxide with DNA at a primer- Template junction
AU - Singh, Suresh B.
AU - Beard, William A.
AU - Hingerty, Brian E.
AU - Wilson, Samuel H.
AU - Broyde, Suse
PY - 1998/1/20
Y1 - 1998/1/20
N2 - A molecular dynamics simulation has been carried out with DNA polymerase β (ν pol) complexed with a DNA primer-template. The templating guanine at the polymerase active site was covalently modified by the carcinogenic metabolite of benzo[a]pyrene, (+)-anti-benzo[a]pyrene diol epoxide, to form the major (+)-trans-anti-benzo[a]pyrene diol epoxide covalent adduct. Thus, the benzo-[a]pyrenyl moiety (BP) is situated in the single-stranded template at the junction between double- and single-stranded DNA. The starting structure was based on the X-ray crystal structure of the rat β pol primer- template and ddCTP complex [Pelletier, H., Sawaya, M. R., Kumar, A., Wilson, S. H., and Kraut, J. (1994) Science 264, 1891-1903]. During the simulation, the BP and its attached templating guanine rearrange to form a structure in which the BP is closer to parallel with the adjacent base pair. In addition, the templating attached guanine is displaced toward the major groove side and access to its Watson-Crick edge is partly obstructed. This structure is stabilized, in part, by new hydrogen bonds between the BP and β pol Asn279 and Arg283. These residues are within hydrogen bonding distance to the incoming ddCTP and templating guanine, respectively, in the crystal structure of the β pol ternary complex. Site-directed mutagenesis has confirmed their role in dNTP binding, discrimination, and catalytic efficiency [Beard, W. A., Osheroff, W. P., Prasad, R., Sawaya, M. R., Jaju, M., Wood, T. G., Kraut, J., Kunkel, T. A., and Wilson, S. H. (1996) J. Biol. Chem. 271, 12141-12144]. The predominant biological effect of the BP is DNA polymerase blockage. Consistent with this biological effect, the computed structure suggests the possibility that the BP's main deleterious impact on DNA synthesis might result at least in part from its specific interactions with key polymerase side chains. Moreover, relatively modest movement of BP and its attached guanine, with some concomitant enzyme motion, is necessary to relieve the obstruction and permit the observed rare incorporation of a dATP opposite the guanine lesion.
AB - A molecular dynamics simulation has been carried out with DNA polymerase β (ν pol) complexed with a DNA primer-template. The templating guanine at the polymerase active site was covalently modified by the carcinogenic metabolite of benzo[a]pyrene, (+)-anti-benzo[a]pyrene diol epoxide, to form the major (+)-trans-anti-benzo[a]pyrene diol epoxide covalent adduct. Thus, the benzo-[a]pyrenyl moiety (BP) is situated in the single-stranded template at the junction between double- and single-stranded DNA. The starting structure was based on the X-ray crystal structure of the rat β pol primer- template and ddCTP complex [Pelletier, H., Sawaya, M. R., Kumar, A., Wilson, S. H., and Kraut, J. (1994) Science 264, 1891-1903]. During the simulation, the BP and its attached templating guanine rearrange to form a structure in which the BP is closer to parallel with the adjacent base pair. In addition, the templating attached guanine is displaced toward the major groove side and access to its Watson-Crick edge is partly obstructed. This structure is stabilized, in part, by new hydrogen bonds between the BP and β pol Asn279 and Arg283. These residues are within hydrogen bonding distance to the incoming ddCTP and templating guanine, respectively, in the crystal structure of the β pol ternary complex. Site-directed mutagenesis has confirmed their role in dNTP binding, discrimination, and catalytic efficiency [Beard, W. A., Osheroff, W. P., Prasad, R., Sawaya, M. R., Jaju, M., Wood, T. G., Kraut, J., Kunkel, T. A., and Wilson, S. H. (1996) J. Biol. Chem. 271, 12141-12144]. The predominant biological effect of the BP is DNA polymerase blockage. Consistent with this biological effect, the computed structure suggests the possibility that the BP's main deleterious impact on DNA synthesis might result at least in part from its specific interactions with key polymerase side chains. Moreover, relatively modest movement of BP and its attached guanine, with some concomitant enzyme motion, is necessary to relieve the obstruction and permit the observed rare incorporation of a dATP opposite the guanine lesion.
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U2 - 10.1021/bi9720639
DO - 10.1021/bi9720639
M3 - Article
C2 - 9454577
AN - SCOPUS:0032548472
SN - 0006-2960
VL - 37
SP - 878
EP - 884
JO - Biochemistry
JF - Biochemistry
IS - 3
ER -