EPR spectroscopy shows a microtubule-dependent conformational change in the kinesin switch 1 domain

Nariman Naber*, Sarah Rice, Marija Matuska, Ronald D. Vale, Roger Cooke, Edward Pate

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


We have used site-directed spin-labeling and electron paramagnetic resonance spectroscopy to monitor a conformational change at the nucleotide site of kinesin. Cys-lite kinesin (K349 monomer) with the mutation S188C was spin labeled with MSL or MTSL. This residue is at the junction between the switch 1 region (which is a structure known to be sensitive to bound nucleotide in the G-proteins) and the α3-helix, adjacent to the nucleotide site. The spectra showed two or more components of mobility, which were independent of nucleotide in the absence of microtubules (MTs). The spectra of both labels showed a change of mobility upon binding to MTs. A more mobile spectral component became enhanced for all triphosphate analogs examined, AMPPNP, ADP•AIFx, or ADP•BeFx, in the presence of MTs, although the magnitude of the new component and the degree of mobility varied with nucleotide analog. The ADP state showed a much-reduced spectral change with a small shift to the more immobilized component in the presence of MTs. For kinesin•ADP•MT, a van't Hoff plot gave ΔH° = -96 kJ/mol implying that the conformational change was extensive. We conclude there is a conformational change in the switch 1-α3-helix domain when kinesin binds to MTs.

Original languageEnglish (US)
Pages (from-to)3190-3196
Number of pages7
JournalBiophysical Journal
Issue number5
StatePublished - May 1 2003

ASJC Scopus subject areas

  • Biophysics


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