85-1411-08　［取扱停止］Glucose Regulated Protein E, Recombinant (GrpE) 200ug　G3057-60

特徴

• GrpE is an acidic 24kD protein which is encoded by a monocistronic Escherichia coli gene (located at 56 min.) which is under the control of both s32 and s70 transcription factors (1). The GrpE protein is a so-called co-chaperone because it is known to assist the DnaK (Hsp70) protein to effectively carry out DnaK-dependent chaperone activity (i.e. protein folding, protein transport, disaggregation of heat inactivated proteins, activation of mutant protein). This auxiliary role is critical to DnaK’s chaperone biology since the grpE gene could not be deleted in a wild type background unless the host E. coli were previously adapted for deletions of the DnaK gene through the accumulation of extragenic suppressers. Also, in vitro these two proteins functionally interact; GrpE protein forms a salt resistant complex with DnaK protein, which is disrupted by ATP (1). It is suggested that DnaK and DnaJ assist protein folding by stabilizing an intermediate conformation; where as the GrpE protein, in an ATP-dependent reaction release partially folded protein from the DnaK/J complex and transfer this immature protein to the GroEL/ES chaperone complex to finish the protein folding reaction. In some cases DnaK/GrpE could act independently of DnaJ chaperone protein: the “inactive” form of DnaA5 mutant protein is activated in the presence of the DnaK and GrpE proteins, and the presence of DnaJ inhibit this reaction. GrpE co-chaperone protein assists DnaK chaperone during two crucial steps: binding to protein substrate and releasing DnaK chaperone from the complex with substrate.
• Activity Assay:The specific activity of GrpE was estimated to be 5x10e5U/mg, where one unit of activity is defined as the incorporation of 1pmol of nucleotides per 1 min. at 30°C into lambdaDNA during in vitro lambdaDNA replication reaction (1). Tested positive for its ability to stimulate DnaKís activity in the presence of DnaJ (2). It has also tested positive for its reactivation in an assay of heat-inactivated firefly luciferase (2).
• Applications:Suitable for use in Functional Activity Assay and Western Blot. Other applications not tested.
• Recommended Dilution:Western Blot: 50-100ng per lane
• Use G8980-25 GroES Pab RbxOptimal dilutions to be determined by the researcher.
• Storage and Stability:For long-term storage, aliquot to avoid repeated freezing and thawing and freeze at -70°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Aliquots are stable for at least 12 months.