Truglio James J, Croteau Deborah L, Skorvaga Milan, DellaVecchia Matthew J, Theis Karsten, Mandavilli Bhaskar S, Van Houten Bennett, Kisker Caroline
Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, NY, USA.
EMBO J. 2004 Jul 7;23(13):2498-509. doi: 10.1038/sj.emboj.7600263. Epub 2004 Jun 10.
Nucleotide excision repair (NER) is a highly conserved DNA repair mechanism present in all kingdoms of life. UvrB is a central component of the bacterial NER system, participating in damage recognition, strand excision and repair synthesis. None of the three presently available crystal structures of UvrB has defined the structure of domain 2, which is critical for the interaction with UvrA. We have solved the crystal structure of the UvrB Y96A variant, which reveals a new fold for domain 2 and identifies highly conserved residues located on its surface. These residues are restricted to the face of UvrB important for DNA binding and may be critical for the interaction of UvrB with UvrA. We have mutated these residues to study their role in the incision reaction, formation of the pre-incision complex, destabilization of short duplex regions in DNA, binding to UvrA and ATP hydrolysis. Based on the structural and biochemical data, we conclude that domain 2 is required for a productive UvrA-UvrB interaction, which is a pre-requisite for all subsequent steps in nucleotide excision repair.
核苷酸切除修复(NER)是一种在所有生命王国中都存在的高度保守的DNA修复机制。UvrB是细菌NER系统的核心组成部分,参与损伤识别、链切除和修复合成。目前已有的三种UvrB晶体结构均未确定对与UvrA相互作用至关重要的结构域2的结构。我们解析了UvrB Y96A变体的晶体结构,该结构揭示了结构域2的一种新折叠,并确定了位于其表面的高度保守残基。这些残基局限于UvrB对DNA结合重要的一侧,可能对UvrB与UvrA的相互作用至关重要。我们对这些残基进行了突变,以研究它们在切口反应、切口前复合物形成、DNA中短双链区域的去稳定化、与UvrA结合以及ATP水解中的作用。基于结构和生化数据,我们得出结论,结构域2是UvrA-UvrB有效相互作用所必需的,而这种相互作用是核苷酸切除修复中所有后续步骤的先决条件。