Conformational plasticity and dynamics in the generic protein folding catalyst SlyD unraveled by single-molecule FRET |
| |
Authors: | Kahra Dana Kovermann Michael Löw Christian Hirschfeld Verena Haupt Caroline Balbach Jochen Hübner Christian Gerhard |
| |
Institution: | 1 Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23564 Lübeck, Germany2 Institut für Physik, Biophysik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale), Germany3 Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden |
| |
Abstract: | The relation between conformational dynamics and chemistry in enzyme catalysis recently has received increasing attention. While, in the past, the mechanochemical coupling was mainly attributed to molecular motors, nowadays, it seems that this linkage is far more general. Single-molecule fluorescence methods are perfectly suited to directly evidence conformational flexibility and dynamics. By labeling the enzyme SlyD, a member of peptidyl-prolyl cis-trans isomerases of the FK506 binding protein type with an inserted chaperone domain, with donor and acceptor fluorophores for single-molecule fluorescence resonance energy transfer, we directly monitor conformational flexibility and conformational dynamics between the chaperone domain and the FK506 binding protein domain. We find a broad distribution of distances between the labels with two main maxima, which we attribute to an open conformation and to a closed conformation of the enzyme. Correlation analysis demonstrates that the conformations exchange on a rate in the 100 Hz range. With the aid from Monte Carlo simulations, we show that there must be conformational flexibility beyond the two main conformational states. Interestingly, neither the conformational distribution nor the dynamics is significantly altered upon binding of substrates or other known binding partners. Based on these experimental findings, we propose a model where the conformational dynamics is used to search the conformation enabling the chemical step, which also explains the remarkable substrate promiscuity connected with a high efficiency of this class of peptidyl-prolyl cis-trans isomerases. |
| |
Keywords: | PPIase peptidyl-prolyl cis-trans isomerase FKBP FK506 binding protein smFRET single-molecule fluorescence resonance energy transfer TtSlyD SlyD from Thermus thermophilus EcSlyD Escherichia coli SlyD IF inserted-in-flap |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|