PDBsum entry: 1fw6

Replication/DNA

PDB id: 1fw6

Contents

Protein chains

759 a.a. *

DNA/RNA

Ligands

SO4 ×4

ADP ×2

Metals

_MG ×2

Waters ×228

* Residue conservation analysis

PDB id:

1fw6

Name:

Replication/DNA

Title:

Crystal structure of a taq muts-DNA-adp ternary complex

Structure:

5'- d( Gp Cp Gp Ap Cp Gp Cp Tp Ap Gp Cp Gp Tp Gp Cp Gp Gp Cp Tp Cp Gp Tp C)-3'. Chain: c. Engineered: yes. 5'- d( Gp Gp Ap Cp Gp Ap Gp Cp Cp Gp Cp Cp Gp Cp Tp Ap Gp Cp Gp Tp Cp G)-3'. Chain: d.

Source:

Synthetic: yes. Thermus aquaticus. Organism_taxid: 271. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Tetramer (from PQS)

Resolution:

2.70Å R-factor: 0.218 R-free: 0.280

Authors:

M.S.Junop,G.Obmolova,K.Rausch,P.Hsieh,W.Yang

Key ref:

M.S.Junop et al. (2001). Composite active site of an ABC ATPase: MutS uses ATP to verify mismatch recognition and authorize DNA repair. Mol Cell, 7, 1. PubMed id: 11172706 DOI: 10.1016/S1097-2765(01)00149-6

Date:

21-Sep-00 Release date: 19-Feb-01

Protein chains

Q56215  (MUTS_THEAQ) -  DNA mismatch repair protein mutS

Seq: 811 a.a.

Struc: 759 a.a.

 Gene Ontology (GO) functional annotation 

• Biological process: response to DNA damage stimulus (3 terms)
• Biochemical function: nucleotide binding (4 terms)

DOI no: 10.1016/S1097-2765(01)00149-6

Mol Cell 7:1 (2001)

PubMed id: 11172706

Composite active site of an ABC ATPase: MutS uses ATP to verify mismatch recognition and authorize DNA repair.

M.S.Junop, G.Obmolova, K.Rausch, P.Hsieh, W.Yang.

ABSTRACT

The MutS protein initiates DNA mismatch repair by recognizing mispaired and unpaired bases embedded in duplex DNA and activating endo- and exonucleases to remove the mismatch. Members of the MutS family also possess a conserved ATPase activity that belongs to the ATP binding cassette (ABC) superfamily. Here we report the crystal structure of a ternary complex of MutS-DNA-ADP and assays of initiation of mismatch repair in conjunction with perturbation of the composite ATPase active site by mutagenesis. These studies indicate that MutS has to bind both ATP and the mismatch DNA simultaneously in order to activate the other mismatch repair proteins. We propose that the MutS ATPase activity plays a proofreading role in DNA mismatch repair, verification of mismatch recognition, and authorization of repair.

Selected figure(s)

Figure 2.
Figure 2. Structure of the ATPase Domain(A) A ribbon diagram of the ATPase domains that form the stable dimer interface of MutS. The domain from subunit A is shown in pink, and that from subunit B is shown in blue. The bound ADP, Mg^2+, and sulfate ion that mimics the hydrolyzed γ-phosphate are shown in a ball-and-stick fashion. The nucleotide binding motifs surrounding the ATP binding site of subunit A are highlighted in green. Dashed lines represent disordered loops.(B) A stereo picture of one ATP binding site. Carbon atoms of the ADP are drawn in yellow, those of the protein side chains in light blue, nitrogen atoms in dark blue, and phosphorus and oxygen atoms in red. The backbone of the N-1 motif (Walker A) is drawn in dark blue, and that of N-2 from the adjacent protein subunit is shown in green. Backbone oxygen atoms of the protein are omitted for clarity. Dashed blue lines represent hydrogen bonds.(C) A topology diagram of the ATPase domain.(D) Sequence comparison of the equivalent nucleotide binding motifs in MutS, HisP, and Rad50.

Figure 3.
Figure 3. Schematic Diagrams of the Previously Proposed “Active Translocation” and “Sliding Clamp” ModelsA mismatch site and hemimethylated GATC sequences are indicated by “v” and “CH[3].” In the “translocation” model, an α-like loop structure of DNA was suggested to result from the “bidirectional” translocation of MutS. Although the double-sphere shape of the MutS molecule was thought to be a MutS dimer ([3]), it actually corresponds to two MutS dimers based on the MutS crystal structures ( [37 and 40]). In the “sliding clamp” model ( [17]), a MutS dimer was suggested to be either in an open “Packman” form (ADP bound) or a “closed ring” form (ATP bound) ( [20]). A mismatch site was proposed to stimulate the exchange of ADP for ATP and conformational changes of MutS. According to the crystal structures, the “Packman” form actually represents the MutS structure without DNA ( [40]).

The above figures are reprinted by permission from Cell Press: Mol Cell (2001, 7, 1-0) copyright 2001.

Figures were selected by the author.