Thermal-triggerd proteinquake leads to disassembly of DegP hexamer as an imperative activation step.
The Escherichia coli DegP has been reported to function both as molecular chaperone and protease for the quality control of outer membrane protein biogenesis. Activation of the inactive DegP hexamers was believed to occur via their disassembly into trimeric units and subsequent reassembly into larger oligomers (12-mers and 24-mers). Here, we analyzed the thermal stability and the unfolding dynamics of the different secondary structure components of the DegP hexamers using Fourier transform infrared spectroscopy and temperature-jump nanosecond time-resolved IR difference absorbance spectroscopy. We found that the interfacial secondary structure components possess a degreed thermal stability, with the disassembly of the DegP hexamers follows a "proteinquake" manner, such that the fully exposed parts of the interfacial β-sheets serving as the temperature sensor and epicenter to drive the sequential unfolding/disassembly process that finishes within about 134 ns at room temperature.
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China 100190.
Shanshan
S
Li
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Center for Protein Science, Peking University, Beijing, China 100871.
Rui
R
Wang
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China 100190.
Deyong
D
Li
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Center for Protein Science, Peking University, Beijing, China 100871.
Jing
J
Ma
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China 100190.
Heng
H
Li
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China 100190.
Xiaochuan
X
He
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Center for Protein Science, Peking University, Beijing, China 100871.
Zengyi
Z
Chang
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China 100190.
Yuxiang
Y
Weng
D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D055503:Protein Multimerization; D055550:Protein Stability; D058767:Protein Unfolding; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013816:Thermodynamics
D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; C061682:DegP protease; D012697:Serine Endopeptidases