title: Preheating induced homogeneity of the small heat shock protein from Methanococcus jannaschii.
abstract: Small heat shock proteins usually exhibit increased chaperone-like activity either at high temperatures or after preheating. However, the activation mechanism is still unclear. In the current study, we investigated the preheating-activation process of Mj HSP16.5, using various biophysical methods. Although Mj HSP16.5 was reported to be the most monodispersed sHSPs, we found that the newly purified Mj HSP16.5 was actually heterogeneous. 85 degrees C-preheating could activate Mj HSP16.5 and turn it into a more compact homogeneous species at the same time. Different cooling rates after preheating did not change the activity of Mj HSP16.5, suggesting that the 85 degrees C-preheated Mj HSP16.5 is in the most active and also the most stable state. These results demonstrate that the activation process of Mj HSP16.5 might accompany a refolding process.
authors.affiliation: State Key Laboratory of Structural Chemistry for Stable and Unstable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. can@pku.edu.cn
authors.forename: Aoneng
authors.initials: A
authors.lastname: Cao
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Wei
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.forename: Luhua
authors.initials: L
authors.lastname: Lai
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D006360:Heat-Shock Proteins / Q000737:chemistry*; D050888:Heat-Shock Proteins, Small / Q000737:chemistry*; D006358:Hot Temperature; D020033:Protein Isoforms / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; C113795:HSP16.5 protein, Methanococcus jannaschii; D006360:Heat-Shock Proteins; D050888:Heat-Shock Proteins, Small; D020033:Protein Isoforms