3fmt

Crystal structure of SeqA bound to DNA

spinqualitylabelsall models 3fmt, resolution 2.98Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3fmt is a 8 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MPD NonStd Res: 6MA Related: 1lrr, 1xrx, 1j3e, 1iu3 Gene: b0687, JW0674, seqA (ECOLI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SEQA_ECOLI] Negative regulator of replication initiation, which contributes to regulation of DNA replication and ensures that replication initiation occurs exactly once per chromosome per cell cycle. Binds to pairs of hemimethylated GATC sequences in the oriC region, thus preventing assembly of replication proteins and re-initiation at newly replicated origins. Repression is relieved when the region becomes fully methylated. Can also bind to hemimethylated GATC sequences outside of oriC region. Binds, with less affinity, to fully methylated GATC sites and affects timing of replication. May play a role in chromosome organization and gene regulation. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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. Structural insights into the cooperative binding of SeqA to a tandem GATC repeat.,Chung YS, Brendler T, Austin S, Guarne A Nucleic Acids Res. 2009 Jun;37(10):3143-52. Epub 2009 Mar 20. PMID:19304745 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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