DNA RECOMBINATION. Base triplet stepping by the Rad51/RecA family of recombinases

Ja Yil Lee; Tsuyoshi Terakawa; Zhi Qi; Justin B Steinfeld; Sy Redding; YoungHo Kwon; William A Gaines; Weixing Zhao; Patrick Sung; Eric C Greene

doi:10.1126/science.aab2666

DNA RECOMBINATION. Base triplet stepping by the Rad51/RecA family of recombinases

Science. 2015 Aug 28;349(6251):977-81. doi: 10.1126/science.aab2666.

Authors

Affiliations

¹ Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
² Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA. Department of Biophysics, Kyoto University, Sakyo, Kyoto, Japan.
³ Department of Chemistry, Columbia University, New York, NY, USA.
⁴ Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA.
⁵ Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA. Howard Hughes Medical Institute, Columbia University, New York, NY, USA. ecg2108@cumc.columbia.edu.

Abstract

DNA strand exchange plays a central role in genetic recombination across all kingdoms of life, but the physical basis for these reactions remains poorly defined. Using single-molecule imaging, we found that bacterial RecA and eukaryotic Rad51 and Dmc1 all stabilize strand exchange intermediates in precise three-nucleotide steps. Each step coincides with an energetic signature (0.3 kBT) that is conserved from bacteria to humans. Triplet recognition is strictly dependent on correct Watson-Crick pairing. Rad51, RecA, and Dmc1 can all step over mismatches, but only Dmc1 can stabilize mismatched triplets. This finding provides insight into why eukaryotes have evolved a meiosis-specific recombinase. We propose that canonical Watson-Crick base triplets serve as the fundamental unit of pairing interactions during DNA recombination.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Amino Acid Sequence
Base Pairing
Base Sequence
Cell Cycle Proteins / chemistry
Cell Cycle Proteins / metabolism
DNA / chemistry*
DNA / metabolism*
DNA, Single-Stranded / metabolism
DNA-Binding Proteins / chemistry
DNA-Binding Proteins / metabolism
Escherichia coli Proteins / chemistry
Escherichia coli Proteins / metabolism
Evolution, Molecular
Homologous Recombination*
Humans
Meiosis
Molecular Dynamics Simulation
Molecular Sequence Data
Rad51 Recombinase / chemistry
Rad51 Recombinase / metabolism*
Rec A Recombinases / chemistry
Rec A Recombinases / metabolism*
Recombinases / chemistry
Recombinases / metabolism*
Saccharomyces cerevisiae Proteins / chemistry
Saccharomyces cerevisiae Proteins / metabolism*
Thermodynamics

Substances

Cell Cycle Proteins
DMC1 protein, S cerevisiae
DNA, Single-Stranded
DNA-Binding Proteins
Escherichia coli Proteins
Recombinases
Saccharomyces cerevisiae Proteins
DNA
RAD51 protein, S cerevisiae
RAD51 protein, human
Rad51 Recombinase
Rec A Recombinases
DMC1 protein, human

Abstract

Publication types

MeSH terms

Substances

Grants and funding