Hsp70 together with the two effector proteins Ydj1 and Sti1 exhibits chaperone activity towards luciferase. Sti1/Hop is essential for the transfer of non-native proteins from Hsp70 to Hsp90
hsp90 is responsible for controlling the conformation, stability, activation, intracellular disposition, and proteolytic turnover of numerous important proteins that are involved in cell growth differentiation and survival
HSP70 can bind to sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA1a) and, depending on the severity of heat stress, protect SERCA1a function by stabilizing the nucleotide binding N-domain
HSP70 can bind to sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA1a) and, depending on the severity of heat stress, protect SERCA1a function by stabilizing the nucleotide binding N-domain
Hsp104 mediates the solubilization of aggregated proteins in an ATP-dependent process assisted by the Hsp70/40 system. The affinity of Hsp104 toward polypeptides is regulated by nucleotides. In the presence of ATP or adenosine-5 -O -(3-thiotriphosphate), the chaperone forms complexes with reduced,carboxymethylated alpha-lactalbumin (RCMLa), a permanently unfolded model substrate. No binding is observed in the presence of ADP. The occupation of the N-terminally located nucleotide-binding domain with ATP seems to be crucial for substrate interaction. When ATP binding to this domain is impaired by mutation,Hsp104 loses its ability to interact with RCMLa. Upon association with a polypeptide,a conformational change occurs within Hsp104 that strongly reduces the dynamics of nucleotide exchange and commits the bound polypeptide to ATP hydrolysis
SyClpC displays intrinsic chaperone activity in vitro, first by preventing aggregation of unfolded polypeptides and second by resolubilizing and refolding aggregated proteins into their native structures. The refolding activity of SyClpC is enhanced 3fold in presence of Bacillus subtilis ClpC adaptor protein MecA
inactivation of the clpC1 gene encoding a chloroplast Hsp100 molecular chaperone causes growth retardation, leaf chlorosis, lower photosynthetic activity, and a specific reduction in photosystem content
Hsp104 can unfold native protein structures such as green fluorescence protein fused to amino acid residues 1-70 of RepA if ATP and ATP-gammaS are present. No cochaperones are required
development and optimization of an ion exchange liquid chromatography method for the determination of ATP, ADP and AMP, for the direct separation, identification and determination of the adenosine nucleotides using a small disk shaped monolithic ethylenediamine column, specifically aimed at the determination of the ATP-ase activity of human heat shock protein 90, Hsp90, detailed overview
PfClpB1 reactivates aggregated firefly luciferase, but the PfClpB1-mediated aggregate reactivation is inhibited in the presence of Escherichia coli DnaK, DnaJ, and GrpE. The lack of effective cooperation between PfClpB1 and the bacterial DnaK system may arise from the Plasmodium-specific sequence of the ClpB middle domain. The recombinant PfClpB1 interacts with and reactivates aggregated luciferase even in the absence of the co-chaperones
PfClpB1 reactivates aggregated firefly luciferase, but the PfClpB1-mediated aggregate reactivation is inhibited in the presence of Escherichia coli DnaK, DnaJ, and GrpE. The lack of effective cooperation between PfClpB1 and the bacterial DnaK system may arise from the Plasmodium-specific sequence of the ClpB middle domain. The recombinant PfClpB1 interacts with and reactivates aggregated luciferase even in the absence of the co-chaperones
Hsp104 can unfold native protein structures such as green fluorescence protein fused to amino acid residues 1-70 of RepA if ATP and ATP-gammaS are present. No cochaperones are required
effect of nucleotides on the formation of the cross-linked adduct: addition of ATP or ADP after formation of the mtHsp70-Hep1 complex leads to release and addition of ATPgammaS to partial release of mtHsp70 from Hep1, whereas almost no mtHsp70 dissociates from Hep1 upon addition of AMP-PNP
following its assembly, the Fe-S cluster is transferred from the Isu scaffold to a recipient protein. Transfer requires the Hsp70 chaperone system consisting of Hsp70 Ssq1, J-protein cochaperone Hsc20, and nucleotide exchange factor Mge1
Hsp14.0 exists as a spherical 24-meric oligomer showing molecular chaperone activity, e.g. to protect thermophilic 3-isopropylmalate dehydrogenase from thermal aggregation at 87°C, while Hsp19.7 of Sulfolobus tokodaii forms a filamentous structure in vivo consisting of spherical particles and lacks molecular chaperone activity
Hsp14.0 exists as a spherical 24-meric oligomer showing molecular chaperone activity, e.g. to protect thermophilic 3-isopropylmalate dehydrogenase from thermal aggregation at 87°C, while Hsp19.7 of Sulfolobus tokodaii forms a filamentous structure in vivo consisting of spherical particles and lacks molecular chaperone activity
enzyme forms dimers and monomers to function as a holding chaperone under stress conditions, whereas it forms a hexamer ring to function as a chaperone in cooperation with KJE and ATP under poststress conditions
the hexameric, nonstress form of ClpB reactivates heat-aggregated proteins dependent on the DnaK system and ATP. The mixture of dimer and monomer, which is formed under stress conditions, protects substrate proteins from thermal inacivation and aggregation