Determinants of Photolyase's DNA Repair Mechanism in Mesophiles and Extremophiles.

Published

Journal Article

Light-driven DNA repair by extremophilic photolyases is of tremendous importance for understanding the early development of life on Earth. The mechanism for flavin adenine dinucleotide repair of DNA lesions is the subject of debate and has been studied mainly in mesophilic species. In particular, the role of adenine in the repair process is poorly understood. Using molecular docking, molecular dynamics simulations, electronic structure calculations, and electron tunneling pathways analysis, we examined adenine's role in DNA repair in four photolyases that thrive at different temperatures. Our results indicate that the contribution of adenine to the electronic coupling between the flavin and the cyclobutane pyrimidine dimer lesion to be repaired is significant in three (one mesophilic and two extremophilic) of the four enzymes studied. Our analysis suggests that thermophilic and hyperthermophilic photolyases have evolved structurally to preserve the functional position (and thus the catalytic function) of adenine at their high temperatures of operation. Water molecules can compete with adenine in establishing the strongest coupling pathway for the electron transfer repair process, but the adenine contribution remains substantial. The present study also reconciles prior seemingly contradictory conclusions on the role of adenine in mesophile electron transfer repair reactions, showing how adenine-mediated superexchange is conformationally gated.

Full Text

Duke Authors

Cited Authors

  • Rousseau, BJG; Shafei, S; Migliore, A; Stanley, RJ; Beratan, DN

Published Date

  • February 13, 2018

Published In

Volume / Issue

  • 140 / 8

Start / End Page

  • 2853 - 2861

PubMed ID

  • 29401372

Pubmed Central ID

  • 29401372

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/jacs.7b11926

Language

  • eng