Biomaterial Database

On the role of single-stranded DNA binding protein in recA protein-promoted DNA strand exchange. 1983

M M Cox, and D A Soltis, and Z Livneh, and I R Lehman

RecA protein-promoted DNA strand exchange is greatly stimulated by the single-stranded DNA binding protein (SSB) of Escherichia coli. Stimulation is not a consequence of the binding of SSB to excess single-stranded DNA. It results instead from stabilization of recA protein-single-stranded DNA complexes formed in the presence of ATP and SSB. In the presence of SSB, recA protein does not measurably dissociate from these complexes for up to 90 min. However, in its absence, recA protein moves rapidly between two populations of single-stranded DNA, and complete equilibration occurs with t 1/2 of 17 s. Rapid transfer of recA protein to single-stranded DNA occurs during all stages of DNA strand exchange and does not require ATP. The transfer involves an equilibrium between free and bound recA protein rather than a direct redistribution between single-stranded DNA molecules. Thus, SSB prevents dissociation of recA protein from single-stranded DNA, rendering the binding of the recA protein to single-stranded DNA irreversible. Under these conditions, the pairing phase of the strand exchange reaction is accelerated to the point that it is no longer rate-limiting. These results can explain the relative inefficiency of DNA strand exchange in the absence of SSB.

UI	MeSH Term	Description	Entries
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D011938	Rec A Recombinases	A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.	Rec A Protein,RecA Protein,Recombinases, Rec A
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial