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Publication Abstract from PubMed

Escherichia coli DnaA binds to 9 bp sequences (DnaA boxes) in the replication origin, oriC, to form a complex initiating chromosomal DNA replication. In the present study, we determined the crystal structure of its DNA-binding domain (domain IV) complexed with a DnaA box at 2.1 A resolution. DnaA domain IV contains a helix-turn-helix motif for DNA binding. One helix and a loop of the helix- turn-helix motif are inserted into the major groove and 5 bp (3' two-thirds of the DnaA box sequence) are recognized through base-specific hydrogen bonds and van der Waals contacts with the C5-methyl groups of thymines. In the minor groove, Arg399, located in the loop adjacent to the motif, recognizes three more base pairs (5' one-third of the DnaA box sequence) by base-specific hydrogen bonds. DNA bending by approximately 28 degrees was also observed in the complex. These base-specific interactions explain how DnaA exhibits higher affinity for the strong DnaA boxes (R1, R2 and R4) than the weak DnaA boxes (R3 and M) in the replication origin.

Structural basis of replication origin recognition by the DnaA protein.,Fujikawa N, Kurumizaka H, Nureki O, Terada T, Shirouzu M, Katayama T, Yokoyama S Nucleic Acids Res. 2003 Apr 15;31(8):2077-86. PMID:12682358^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.