Referenced in: none

Automatically associated channels: Kv10.1

Title: Cooperative binding of Agrobacterium tumefaciens VirE2 protein to single-stranded DNA.

Authors: P Sen, G J Pazour, D Anderson, A Das

Journal, date & volume: J. Bacteriol., 1989 May , 171, 2573-80

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/2708313

Abstract
The VirE2 protein of Agrobacterium tumefaciens Ti plasmid pTiA6 is a single-stranded-DNA-binding protein. Density gradient centrifugation studies showed that it exists as a tetramer in solution. Monomeric VirE2 active in DNA binding could also be obtained by using a different protein isolation procedure. VirE2 was found to be thermolabile; brief incubation at 37 degrees C abolished its DNA-binding activity. It was insensitive to the sulfhydryl-specific reagent N-ethylmaleimide. Removal of the carboxy-terminal 37 residues of the 533-residue VirE2 polypeptide led to complete loss of DNA-binding activity; however, chimeric fusion proteins containing up to 125 residues of the VirE2 C terminus were inactive in DNA binding. In nuclease protection studies, VirE2 protected single-stranded DNA against degradation by DNase I. Analysis of the DNA-VirE2 complex by electron microscopy demonstrated that VirE2 coats a single-stranded DNA molecule and that the binding of VirE2 to its substrate is cooperative.