3FMT

Crystal structure of SeqA bound to DNA

Summary for 3FMT

• Entry DOI: 10.2210/pdb3fmt/pdb
• Related: 1IU3 1J3E 1LRR 1XRX
• Descriptor: Protein seqA, 5'-D(*GP*AP*GP*TP*CP*GP*(6MA)P*TP*CP*GP*GP*CP*GP*GP*GP*(6MA)P*TP*CP*CP*TP*TP*A)-3', 5'-D(*TP*CP*TP*AP*AP*GP*GP*AP*TP*CP*CP*CP*GP*CP*CP*GP*AP*TP*CP*GP*AP*C)-3', ... (5 entities in total)
• Functional Keywords: protein-dna complex, hemimethylated gatc, dna replication, sequestration, dna replication inhibitor, dna-binding, replication inhibitor-dna complex, replication inhibitor/dna
• Biological source: Escherichia coli; More
• Cellular location: Cytoplasm : P0AFY8
• Total number of polymer chains: 8
• Total formula weight: 101705.75

Authors

Chung, Y.S.,Brendler, T.,Austin, S.,Guarne, A. (deposition date: 2008-12-22, release date: 2009-04-28, Last modification date: 2023-09-06)

Primary citation

Chung, Y.S.,Brendler, T.,Austin, S.,Guarne, A.
Structural insights into the cooperative binding of SeqA to a tandem GATC repeat
Nucleic Acids Res., 37:3143-3152, 2009

PubMed Abstract: SeqA is a negative regulator of DNA replication in Escherichia coli and related bacteria that functions by sequestering the origin of replication and facilitating its resetting after every initiation event. Inactivation of the seqA gene leads to unsynchronized rounds of replication, abnormal localization of nucleoids and increased negative superhelicity. Excess SeqA also disrupts replication synchrony and affects cell division. SeqA exerts its functions by binding clusters of transiently hemimethylated GATC sequences generated during replication. However, the molecular mechanisms that trigger formation and disassembly of such complex are unclear. We present here the crystal structure of a dimeric mutant of SeqA [SeqADelta(41-59)-A25R] bound to tandem hemimethylated GATC sites. The structure delineates how SeqA forms a high-affinity complex with DNA and it suggests why SeqA only recognizes GATC sites at certain spacings. The SeqA-DNA complex also unveils additional protein-protein interaction surfaces that mediate the formation of higher ordered complexes upon binding to newly replicated DNA. Based on this data, we propose a model describing how SeqA interacts with newly replicated DNA within the origin of replication and at the replication forks.

PubMed: 19304745
DOI: 10.1093/nar/gkp151

Experimental method

X-RAY DIFFRACTION (2.983 Å)