1xrx
From Proteopedia
Crystal structure of a DNA-binding protein
Overview
Escherichia coli SeqA binds clusters of transiently hemimethylated GATC sequences and sequesters the origin of replication, oriC, from methylation and premature reinitiation. Besides oriC, SeqA binds and organizes newly synthesized DNA at replication forks. Binding to multiple GATC sites is crucial for the formation of stable SeqA-DNA complexes. Here we report the crystal structure of the oligomerization domain of SeqA (SeqA-N). The structural unit of SeqA-N is a dimer, which oligomerizes to form a filament. Mutations that disrupt filament formation lead to asynchronous DNA replication, but the resulting SeqA dimer can still bind two GATC sites separated from 5 to 34 base pairs. Truncation of the linker between the oligomerization and DNA-binding domains restricts SeqA to bind two GATC sites separated by one or two full turns. We propose a model of a SeqA filament interacting with multiple GATC sites that accounts for both origin sequestration and chromosome organization.
About this Structure
1XRX is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of a SeqA-N filament: implications for DNA replication and chromosome organization., Guarne A, Brendler T, Zhao Q, Ghirlando R, Austin S, Yang W, EMBO J. 2005 Apr 20;24(8):1502-11. Epub 2005 Mar 31. PMID:15933720 Page seeded by OCA on Sat May 3 15:26:06 2008
