4fn3 | pdb_00004fn3

Crystal Structure of an S52A mutant of the Restriction-Modification Controller Protein C.Esp1396I

spinqualitylabelsall models 4fn3, resolution 1.79Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fn3 is a 2 chain structure with sequence from Enterobacter sp. RFL1396. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8GGH0_9ENTR Publication Abstract from PubMed Bacterial restriction-modification (RM) systems are comprised of two complementary enzymatic activities that prevent the establishment of foreign DNA in a bacterial cell: DNA methylation and DNA restriction. These two activities are tightly regulated to prevent over-methylation or auto-restriction. Many Type II RM systems employ a controller (C) protein as a transcriptional regulator for the endonuclease gene (and in some cases, the methyltransferase gene also). All high-resolution structures of C-protein/DNA-protein complexes solved to date relate to C.Esp1396I, from which the interactions of specific amino acid residues with DNA bases and/or the phosphate backbone could be observed. Here we present both structural and DNA binding data for a series of mutations to the key DNA binding residues of C.Esp1396I. Our results indicate that mutations to the backbone binding residues (Y37, S52) had a lesser affect on DNA binding affinity than mutations to those residues that bind directly to the bases (T36, R46), and the contributions of each side chain to the binding energies are compared. High-resolution X-ray crystal structures of the mutant and native proteins showed that the fold of the proteins was unaffected by the mutations, but also revealed variation in the flexible loop conformations associated with DNA sequence recognition. Since the tyrosine residue Y37 contributes to DNA bending in the native complex, we have solved the structure of the Y37F mutant protein/DNA complex by X-ray crystallography to allow us to directly compare the structure of the DNA in the mutant and native complexes. Structural and Mutagenic Analysis of the RM Controller Protein C.Esp1396I.,Martin RN, McGeehan JE, Kneale G PLoS One. 2014 Jun 2;9(6):e98365. doi: 10.1371/journal.pone.0098365. eCollection , 2014. PMID:24887147 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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