Structure and function of the N-terminal 40 kDa fragment of human PMS2: a monomeric GHL ATPase.
Human MutLalpha, a heterodimer of hMLH1 and hPMS2, is essential for DNA mismatch repair. Inactivation of the hmlh1 or hpms2 genes by mutation or epigenesis causes genomic instability and a predisposition to hereditary non-polyposis cancer. We report here the X-ray crystal structures of the conserved N-terminal 40 kDa fragment of hPMS2, NhPMS2, and its complexes with ATPgammaS and ADP at 1.95, 2.7 and 2.7 A resolution, respectively. The NhPMS2 structures closely resemble the ATPase fragment of Escherichia coli MutL, which coordinates protein-protein interactions in mismatch repair by undergoing structural transformation upon binding of ATP. Unlike the E.coli MutL, whose ATPase activity requires protein dimerization, the monomeric form of NhPMS2 is active both in ATP hydrolysis and DNA binding. NhPMS2 is the first example of a GHL ATPase active as a monomer, suggesting that its activity may be modulated by hMLH1 in MutLalpha, and vice versa. The potential heterodimer interface revealed by crystallography provides a mutagenesis target for functional studies of MutLalpha.
Guarné
A
A
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Junop
M S
MS
Yang
W
W
D000251:Adenosine Triphosphatases / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D020137:Base Pair Mismatch; D001665:Binding Sites; D002352:Carrier Proteins; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics; D018360:Crystallography, X-Ray; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000737:chemistry*; D029968:Escherichia coli Proteins; D006801:Humans; D000070976:Mismatch Repair Endonuclease PMS2; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000070956:MutL Proteins; D009363:Neoplasm Proteins; D010446:Peptide Fragments / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C074770:MutL protein, E coli; D009363:Neoplasm Proteins; C088996:PMS1 protein, human; D010446:Peptide Fragments; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C094934:PMS2 protein, human; D000070976:Mismatch Repair Endonuclease PMS2; D000070956:MutL Proteins; D045643:DNA Repair Enzymes