1LRR: Crystal Structure Of E. Coli Seqa Complexed With Hemimethylated Dna

The SeqA protein binds clusters of fully methylated or hemimethylated GATC sequences at oriC and negatively modulates the initiation of DNA replication. We find that SeqA can be proteolytically cleaved into an N-terminal multimerization and a C-terminal DNA-binding domain and have determined the crystal structure of the C-terminal domain in complex with a hemimethylated GATC site. SeqA makes direct hydrogen bonds and van der Waals contacts with the hemimethylated A-T base pair in addition to interactions with the surrounding bases and DNA backbone. The tetrameric protein-DNA complex found in the crystal suggests that SeqA binds multiple GATC sites on separate DNA duplexes, altering the overall DNA topology and sequestering oriC from replication initiation.
PDB ID: 1LRRDownload
MMDB ID: 73999
PDB Deposition Date: 2002/5/15
Updated in MMDB: 2009/07
Experimental Method:
x-ray diffraction
Resolution: 2.65  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 1LRR: trimeric; determined by author
Molecular Components in 1LRR
Label Count Molecule
Protein (1 molecule)
Seqa Protein
Molecule annotation
Nucleotides(2 molecules)
Molecule annotation
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB