UvsY is the phage T4 recombination mediator protein, and structural and biophysical studies provide insights into its role in T4 homologous recombination. During T4 homologous recombination, the UvsX recombinase must compete with the prebound gp32 single-stranded binding protein for DNA-binding sites and T4 UvsY Protein stimulates this filament nucleation event (1). UvsY is a 15.8-kDa protein with properties that are consistent with its role as mediator; it stimulates the DNA-dependent ATPase activity of UvsX, lowers the critical concentration of UvsX that is required for activity, and promotes strand exchange (2, 3). UvsY efficiently promotes the UvsX-catalyzed strand invasion reaction by recruiting to ssDNA–gp32 complexes, promotes the release of gp32, and favors the binding of UvsX.Note:Glycerol acts as a cryoprotectant and protein stabilizer when added to the storage buffer of proteins and enzymes. However, in certain circumstances, it is preferred to omit glycerol from the buffer. This includes instances where the presence of glycerol may interfere, such as lyophilization, high-throughput instruments with sensitive fluidics or primary cell cultures.For our glycerol free products, it is recommended to use immediately upon thaw as without glycerol there will be significant activity loss with freeze/thaw cycles.Protein PurityThe physical purity of this enzyme is ≥98% as assessed by SDS-PAGE with Coomassie® blue staining (Fig. 1).Product SourceE. coli BL21 (DE3) strain expressing T4 UvsY gene with an Nterminal His tag.This GST tag does not have any effect on UvsY activity.Product IncludesGlycerol Free T4 UvsY protein10X UvsY Reaction Buffer1x UvsY reaction buffer composition20 mM Tris-acetate100 mM Potassium acetate10 mM Magnesium acetate1 mM DTTpH 7.8 @ 25ºCStorage Buffer50 mM Tris-HCl50 mM KCl1 mM DTT0.1 mM EDTApH 7.5 @ 25ºCStorage Temperature-20ºCQuality Control assaysGlycerol Free T4 UvsY is free from detectable nuclease activities.References1. Beernink HT, Morrical SW. RMPs: Recombination/replication mediator proteins. Trends Biochem Sci. 1999;24(10):385–389.2. Hashimoto K, Yonesaki T. The characterization of a complex of three bacteriophage T4 recombination proteins, uvsX protein, uvsY protein, and gene 32 protein, on single-stranded DNA. JBiol Chem. 1991;266(8):4883–4888.3. Beernink HT, Morrical SW. The uvsY recombination protein of bacteriophage T4 forms hexamers in the presence and absence of single-stranded DNA. Biochemistry. 1998;37(16):5673– 6813572G 3575G 3577G