Biomaterial Database

Mechanism of presynaptic filament stabilization by the bacteriophage T4 UvsY recombination mediator protein. 2006

Jie Liu, and Jeffrey P Bond, and Scott W Morrical

Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.

UvsY is the recombination mediator protein (RMP) of bacteriophage T4, which promotes homologous recombination by facilitating presynaptic filament assembly. The results of previous studies suggest that UvsY promotes the assembly of presynaptic filaments in part by stabilizing interactions between T4 UvsX recombinase and single-stranded DNA (ssDNA). To test this hypothesis, we studied the interactions of UvsX and UvsY with a fluorescein-derivatized oligonucleotide. This assay distinguishes between bipartite UvsX- or UvsY-ssDNA and tripartite UvsX-UvsY-ssDNA complex formation via differential fluorescence quenching effects. Salt stabilities of the three complexes were measured at equilibrium in the presence and absence of various nucleotide ligands of the UvsX protein and also under steady-state conditions for UvsX-catalyzed ssDNA-dependent ATP hydrolysis. The results demonstrate that UvsY globally stabilizes UvsX-ssDNA complexes, consistent with an increase in the apparent equilibrium binding affinity, K(ss)omega, of the UvsX-ssDNA interactions. The UvsY-mediated affinity increase is observed at equilibrium in the presence of ADP, ATPgammaS, or in the absence of the nucleotide and also at steady-state in the presence of ATP. Intriguingly, the stabilizing effects of UvsY and ATPgammaS on UvsX-ssDNA interactions are synergistic, indicating nonredundant mechanisms for UvsX-ssDNA complex stabilization by RMP versus nucleoside triphosphate effectors. Experiments with UvsY missense mutants defective in ssDNA binding demonstrate that UvsY-ssDNA interactions are of major importance in stabilizing UvsX-ssDNA complexes, whereas UvsY-UvsX protein-protein interactions provide residual stabilization energy. Together, the data is consistent with a mechanism in which UvsY stabilizes presynaptic filaments by organizing the ssDNA lattice into a structure that is favorable for UvsX-ssDNA interactions.

UI	MeSH Term	Description	Entries
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
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
D011995	Recombination, Genetic	Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.	Genetic Recombination,Recombination,Genetic Recombinations,Recombinations,Recombinations, Genetic
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D004277	DNA, Single-Stranded	A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.	Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA
D000227	Adenine Nucleotides		Adenine Nucleotide,Adenosine Phosphate,Adenosine Phosphates,Nucleotide, Adenine,Nucleotides, Adenine,Phosphate, Adenosine,Phosphates, Adenosine
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, Adenosine
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D014764	Viral Proteins	Proteins found in any species of virus.	Gene Products, Viral,Viral Gene Products,Viral Gene Proteins,Viral Protein,Protein, Viral,Proteins, Viral