UMass Chan Affiliations
Department of Biochemistry and Molecular PharmacologyDepartment of Molecular Genetics and Microbiology
Graduate School of Biomedical Sciences
Document Type
Journal ArticlePublication Date
2001-01-02Keywords
Base Sequence; DNA Primers; *DNA Repair Enzymes; DNA-Binding Proteins; Endodeoxyribonucleases; Escherichia coli; Escherichia coli Proteins; Models, Molecular; Mutagenesis, Site-Directed; Protein ConformationLife Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
Site-directed mutagenesis was performed on several areas of MutH based on the similarity of MutH and PvuII structural models. The aims were to identify DNA-binding residues; to determine whether MutH has the same mechanism for DNA binding and catalysis as PvuII; and to localize the residues responsible for MutH stimulation by MutL. No DNA-binding residues were identified in the two flexible loop regions of MutH, although similar loops in PvuII are involved in DNA binding. Two histidines in MutH are in a similar position as two histidines (His-84 and His-85) in PvuII that signal for DNA binding and catalysis. These MutH histidines (His-112 and His-115) were changed to alanines, but the mutant proteins had wild-type activity both in vivo and in vitro. The results indicate that the MutH signal for DNA binding and catalysis remains unknown. Instead, a lysine residue (Lys-48) was found in the first flexible loop that functions in catalysis together with the three presumed catalytic amino acids (Asp-70, Glu-77, and Lys-79). Two deletion mutations (MutHDelta224 and MutHDelta214) in the C-terminal end of the protein, localized the MutL stimulation region to five amino acids (Ala-220, Leu-221, Leu-222, Ala-223, and Arg-224).Source
J Biol Chem. 2001 Apr 13;276(15):12113-9. Epub 2000 Dec 21. Link to article on publisher's siteDOI
10.1074/jbc.M007935200Permanent Link to this Item
http://hdl.handle.net/20.500.14038/34115PubMed ID
11124943Related Resources
Link to article in PubMedae974a485f413a2113503eed53cd6c53
10.1074/jbc.M007935200