Structure of a DNA glycosylase searching for lesions.
DNA glycosylases must interrogate millions of base pairs of undamaged DNA in order to locate and then excise one damaged nucleobase. The nature of this search process remains poorly understood. Here we report the use of disulfide cross-linking (DXL) technology to obtain structures of a bacterial DNA glycosylase, MutM, interrogating undamaged DNA. These structures, solved to 2.0 angstrom resolution, reveal the nature of the search process: The protein inserts a probe residue into the helical stack and severely buckles the target base pair, which remains intrahelical. MutM therefore actively interrogates the intact DNA helix while searching for damage.
Banerjee
Anirban
A
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Santos
Webster L
WL
Verdine
Gregory L
GL
D020029:Base Pairing; D001665:Binding Sites; D003432:Cross-Linking Reagents; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004249:DNA Damage; D045647:DNA Glycosylases / Q000737:chemistry* / Q000378:metabolism*; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary
D003432:Cross-Linking Reagents; D009838:Oligodeoxyribonucleotides; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D045647:DNA Glycosylases