Subunit exchange of MjHsp16.5 studied by single-molecule imaging and fluorescence resonance energy transfer.
MjHsp16.5 was separately labeled by fluorescent dye Cy3 and Cy5.5. The dissociation event of a single 24-mer MjHsp16.5 molecule was captured by single-molecule imaging (SMI). Temperature-regulated subunit exchange was revealed by the real-time fluorescence resonance energy transfer (FRET). The combination of single-molecular statistics and kinetic parameters from FRET experiments leads to the conclusion that below 75 degrees C the rate-determining step of the subunit exchange was the dissociation of the dye-labeled 24-mer in which the dimer was intact, whereas above 75 degrees C, smaller units emerged in the exchange and the rate-determining step had the character of a bimolecular reaction.
Guan
Yinghua
Y
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, and Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Wang
Zheng
Z
Cao
Aoneng
A
Lai
Luhua
L
Zhao
Xin Sheng
XS
D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D007700:Kinetics; D008856:Microscopy, Fluorescence; D021122:Protein Subunits / Q000737:chemistry*; D013696:Temperature
D019843:Archaeal Proteins; D005456:Fluorescent Dyes; C113795:HSP16.5 protein, Methanococcus jannaschii; D006360:Heat-Shock Proteins; D021122:Protein Subunits