Crystallographic and Functional Studies of Very Short Patch Repair Endonuclease

• Published in: Molecular cell 1999-05, Vol.3 (5), p.621-628
• Main Authors: Tsutakawa, Susan E, Muto, Takanori, Kawate, Tomohiko, Jingami, Hisato, Kunishima, Naoki, Ariyoshi, Mariko, Kohda, Daisuke, Nakagawa, Masako, Morikawa, Kosuke
• Format: Article
• Language: English
• Subjects: Alanine; Base Pair Mismatch; Catalytic Domain; Conserved Sequence; Crystallography; Deoxyribonucleases, Type II Site-Specific - chemistry; Deoxyribonucleases, Type II Site-Specific - genetics; Deoxyribonucleases, Type II Site-Specific - metabolism; DNA Repair; Endodeoxyribonucleases - chemistry; Endodeoxyribonucleases - genetics; Endodeoxyribonucleases - metabolism; Manganese - metabolism; Molecular Sequence Data; Mutagenesis; Protein Structure, Secondary; Protein Structure, Tertiary; Sequence Homology, Amino Acid; Static Electricity
• ISSN: 1097-2765; 1097-4164; 1097-4164
• DOI: 10.1016/S1097-2765(00)80355-X

Vsr endonuclease plays a crucial role in the repair of TG mismatched base pairs, which are generated by the spontaneous degradation of methylated cytidines; Vsr recognizes the mismatched base pair and cleaves the phosphate backbone 5′ to the thymidine. We have determined the crystal structure of a truncated form of this endonuclease at 1.8 Å resolution. The protein contains one structural zinc-binding module. Unexpectedly, its overall topology resembles members of the type II restriction endonuclease family. Subsequent mutational and biochemical analyses showed that certain elements in the catalytic site are also conserved. However, the identification of a critical histidine and evidence of an active site metal-binding coordination that is novel to endonucleases indicate a distinct catalytic mechanism.