An undecided coiled coil: the leucine zipper of Nek2 kinase exhibits atypical conformational exchange dynamics
Croasdale, R. and Ivins, F.J. and Muskett, F. and Daviter, Tina and Scott, D.J. and Hardy, T. and Smerdon, S.J. and Fry, A.M. and Pfuhl, M. (2011) An undecided coiled coil: the leucine zipper of Nek2 kinase exhibits atypical conformational exchange dynamics. Journal of Biological Chemistry 286 (31), pp. 27537-27547. ISSN 0021-9258.
Leucine zippers are oligomerization domains used in a wide range of proteins. Their structure is based on a highly conserved heptad repeat sequence in which two key positions are occupied by leucines. The leucine zipper of the cell cycle-regulated Nek2 kinase is important for its dimerization and activation. However, the sequence of this leucine zipper is most unusual in that leucines occupy only one of the two hydrophobic positions. The other position, depending on the register of the heptad repeat, is occupied by either acidic or basic residues. Using NMR spectroscopy, we show that this leucine zipper exists in two conformations of almost equal population that exchange with a rate of 17 s−1. We propose that the two conformations correspond to the two possible registers of the heptad repeat. This hypothesis is supported by a cysteine mutant that locks the protein in one of the two conformations. NMR spectra of this mutant showed the predicted 2-fold reduction of peaks in the 15N HSQC spectrum and the complete removal of cross peaks in exchange spectra. It is possible that interconversion of these two conformations may be triggered by external signals in a manner similar to that proposed recently for the microtubule binding domain of dynein and the HAMP domain. As a result, the leucine zipper of Nek2 kinase is the first example where the frameshift of coiled-coil heptad repeats has been directly observed experimentally.
|Keyword(s) / Subject(s):||NMR, Protein Assembly, Protein Conformation, Protein Domains, Signal Transduction, Chemical Exchange, Coiled Coils, Leucine Zippers, Protein Dynamics|
|School:||Birkbeck Schools and Departments > School of Science > Biological Sciences|
|Date Deposited:||20 Apr 2012 09:19|
|Last Modified:||11 Oct 2016 15:26|
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