4m6f
From Proteopedia
Dimer of the G-Segment Invertase bound to a DNA substrate
Structural highlights
FunctionGIN_BPMU Performs inversion of a viral 3 kp segment (G-segment) that encodes two alternate pairs of tail fiber proteins thereby modifying the host specificity of the virus. Binds as a dimer to the viral gix sites which are 34-bp palindromic sequences that flank the invertible G-segment. Catalyzes site-specific recombination in the presence of the host factor Fis. Gin dimers bound to each of the gix sites and host factor Fis bound to the enhancer come together to form the synaptic complex. Each Gin monomer introduces a nick and becomes covalently attached to the 5'-phosphate of the DNA, resulting in double-stranded staggered breaks at both recombination sites. A 180 degrees rotation of one of the two Gin dimers followed by religation of the DNA leads to the inversion of the G-segment (G+ or G- orientation).[1] [2] [3] [4] Publication Abstract from PubMedCrystals of the G-segment invertase in complex with a 37-base-pair asymmetric DNA duplex substrate had an unusually high solvent content of 88% and diffracted to a maximal resolution of about 5.0 A. These crystals exhibited a high degree of non-isomorphism and anisotropy, which presented a serious challenge for structure determination by isomorphous replacement. Here, a procedure of cross-crystal averaging is described that uses large non-isomorphous crystallographic data with a priori information of an approximate molecular boundary as determined from a minimal amount of experimental phase information. Using this procedure, high-quality experimental phases were obtained that have enabled it to be shown that the conformation of the bound substrate DNA duplex significantly differs from those of substrates bound in other serine recombinase-DNA complexes. Exploiting large non-isomorphous differences for phase determination of a G-segment invertase-DNA complex.,Ritacco CJ, Steitz TA, Wang J Acta Crystallogr D Biol Crystallogr. 2014 Mar;70(Pt 3):685-93. doi:, 10.1107/S1399004713032392. Epub 2014 Feb 15. PMID:24598738[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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