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Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu

While most DNA polymerases discriminate against ribonucleotide triphosphate (rNTP) incorporation very effectively, the Family X member DNA polymerase μ (Pol μ) incorporates rNTPs almost as efficiently as deoxyribonucleotides. To gain insight into how this occurs, here we have used X-ray crystallogra...

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Autores principales: Moon, Andrea F., Pryor, John M., Ramsden, Dale A., Kunkel, Thomas A., Bebenek, Katarzyna, Pedersen, Lars C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5587726/
https://www.ncbi.nlm.nih.gov/pubmed/28911097
http://dx.doi.org/10.1093/nar/gkx527
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author Moon, Andrea F.
Pryor, John M.
Ramsden, Dale A.
Kunkel, Thomas A.
Bebenek, Katarzyna
Pedersen, Lars C.
author_facet Moon, Andrea F.
Pryor, John M.
Ramsden, Dale A.
Kunkel, Thomas A.
Bebenek, Katarzyna
Pedersen, Lars C.
author_sort Moon, Andrea F.
collection PubMed
description While most DNA polymerases discriminate against ribonucleotide triphosphate (rNTP) incorporation very effectively, the Family X member DNA polymerase μ (Pol μ) incorporates rNTPs almost as efficiently as deoxyribonucleotides. To gain insight into how this occurs, here we have used X-ray crystallography to describe the structures of pre- and post-catalytic complexes of Pol μ with a ribonucleotide bound at the active site. These structures reveal that Pol μ binds and incorporates a rNTP with normal active site geometry and no distortion of the DNA substrate or nucleotide. Moreover, a comparison of rNTP incorporation kinetics by wildtype and mutant Pol μ indicates that rNTP accommodation involves synergistic interactions with multiple active site residues not found in polymerases with greater discrimination. Together, the results are consistent with the hypothesis that rNTP incorporation by Pol μ is advantageous in gap-filling synthesis during DNA double strand break repair by nonhomologous end joining, particularly in nonreplicating cells containing very low deoxyribonucleotide concentrations.
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spelling pubmed-55877262017-09-11 Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu Moon, Andrea F. Pryor, John M. Ramsden, Dale A. Kunkel, Thomas A. Bebenek, Katarzyna Pedersen, Lars C. Nucleic Acids Res Structural Biology While most DNA polymerases discriminate against ribonucleotide triphosphate (rNTP) incorporation very effectively, the Family X member DNA polymerase μ (Pol μ) incorporates rNTPs almost as efficiently as deoxyribonucleotides. To gain insight into how this occurs, here we have used X-ray crystallography to describe the structures of pre- and post-catalytic complexes of Pol μ with a ribonucleotide bound at the active site. These structures reveal that Pol μ binds and incorporates a rNTP with normal active site geometry and no distortion of the DNA substrate or nucleotide. Moreover, a comparison of rNTP incorporation kinetics by wildtype and mutant Pol μ indicates that rNTP accommodation involves synergistic interactions with multiple active site residues not found in polymerases with greater discrimination. Together, the results are consistent with the hypothesis that rNTP incorporation by Pol μ is advantageous in gap-filling synthesis during DNA double strand break repair by nonhomologous end joining, particularly in nonreplicating cells containing very low deoxyribonucleotide concentrations. Oxford University Press 2017-09-06 2017-06-30 /pmc/articles/PMC5587726/ /pubmed/28911097 http://dx.doi.org/10.1093/nar/gkx527 Text en Published by Oxford University Press on behalf of Nucleic Acids Research 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.
spellingShingle Structural Biology
Moon, Andrea F.
Pryor, John M.
Ramsden, Dale A.
Kunkel, Thomas A.
Bebenek, Katarzyna
Pedersen, Lars C.
Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title_full Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title_fullStr Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title_full_unstemmed Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title_short Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu
title_sort structural accommodation of ribonucleotide incorporation by the dna repair enzyme polymerase mu
topic Structural Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5587726/
https://www.ncbi.nlm.nih.gov/pubmed/28911097
http://dx.doi.org/10.1093/nar/gkx527
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