Fast subdomain folding prior to the global refolding transition of E. coli adenylate kinase: A double kinetics study

Eldad Ben Ishay, Gil Rahamim, Tomer Orevi, Gershon Hazan, Dan Amir, Elisha Haas

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The rate of folding of globular proteins depends on specific local and nonlocal intramolecular interactions. What is the relative role of these two types of interaction at the initiation of refolding? We address this question by application of a double kinetics method based on fast initiation of refolding of site specifically labeled protein samples and detection of the transient distributions of selected intramolecular distances by means of fast measurements of time-resolved fluorescence resonance energy transfer. We determined the distribution of the distance between the ends of a 44-chain segment that includes the AMPbind domain, by labeling residues 28 and 71, in Escherichia coli adenylate kinase (AK) and the distribution of the distance between residues 18 and 203, which depends on the overall order of the molecule. That distribution shows two-state transition to the native intramolecular distance at the same rate as that of the cooperative refolding transition of the AK molecule. In sharp contrast, the distance distribution between residues 28 and 71 is already native like at the end of the dead-time of the mixing device. This fast formation of native short distance between two widely separated chain sections can be either dependent on fast folding of the AMPbind domain or a result of a very effective nonlocal interaction between specific short clusters of hydrophobic residues. Further experiments on studying the kinetics of folding of selected structural elements in the protein will help determination of the driving force of this early folding event.

Original languageEnglish
Pages (from-to)613-623
Number of pages11
JournalJournal of Molecular Biology
Volume423
Issue number4
DOIs
StatePublished - 2 Nov 2012

Bibliographical note

Funding Information:
This study was supported by grants from the Israel Science Foundation ( ISF1464/10 ), the EU Marie Curie Transfer of Knowledge ( 29936 ), the United States–Israel Binational Science Foundation ( BSF2005270 ) and the Damadian Center for Magnetic Resonance Research, Bar-Ilan University .

Funding

This study was supported by grants from the Israel Science Foundation ( ISF1464/10 ), the EU Marie Curie Transfer of Knowledge ( 29936 ), the United States–Israel Binational Science Foundation ( BSF2005270 ) and the Damadian Center for Magnetic Resonance Research, Bar-Ilan University .

FundersFunder number
Damadian Center for Magnetic Resonance Research
European Commission29936
United States-Israel Binational Science FoundationBSF2005270
Bar-Ilan University
Israel Science FoundationISF1464/10

    Keywords

    • double kinetics
    • loop closure
    • nonlocal interactions
    • protein folding
    • time-resolved FRET

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