DNA binding;
mismatch repair;
Mlh1;
Msh2;
Msh6;
Pms1;
D O I:
10.1515/BC.2002.103
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
We describe here our recent studies of the DNA binding properties of Msh2-Msh6 and Mlh1-Pms1, two protein complexes required to repair mismatches generated during DNA replication. Mismatched DNA binding by Msh2-Msh6 was probed by mutagenesis based on the crystal structure of the homologous bacterial MutS homodimer bound to DNA. The results suggest that several amino acid side chains inferred to interact with the DNA backbone near the mismatch are critical for repair activity. These contacts, which are different in Msh2 and Msh6, likely facilitate stacking and hydrogen bonding interactions between side chains in Msh6 and the mismatched base, thus stabilizing a kinked DNA conformation that permits subsequent repair steps coordinated by the Mlh1-Pms1 heterodimer. Mlh1-Pms1 also binds to DNA, but independently of a mismatch. Mlh1-Pms1 binds short DNA substrates with low affinity and with a slight preference for singlestranded DNA. It also binds longer duplex DNA molecules, but with a higher affinity indicative of cooperative binding. Indeed, imaging by atomic force microscopy reveals cooperative DNA binding and simultaneous interaction with two DNA duplexes. The novel DNA binding properties of Mlh1- Pms1 may be relevant to signal transduction during DNA mismatch repair and to recombination, meiosis and cellular responses to DNA damage.
机构:
THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107
BENDE, SM
GRAFSTROM, RH
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机构:
THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107
机构:
Univ Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USAUniv Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USA
Das Gupta, R
Kolodner, RD
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机构:
Univ Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USAUniv Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USA
机构:
THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107
BENDE, SM
GRAFSTROM, RH
论文数: 0引用数: 0
h-index: 0
机构:
THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MICROBIOL & IMMUNOL,PHILADELPHIA,PA 19107
机构:
Univ Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USAUniv Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USA
Das Gupta, R
Kolodner, RD
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USAUniv Calif San Diego, Ludwig Inst Canc Res, Dept Med & Canc Ctr, Sch Med, La Jolla, CA 92093 USA