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EMBO reports 4, 7, 717–722 (2003)
doi:10.1038/sj.embor.embor884
Published online: 1 July 2003
Dimerization properties of a Xenopus laevis kinesin-II carboxy-terminal stalk fragment
Valeria De Marco1, Ario de Marco1, Kenneth N. Goldie1, John J. Correia2 & Andreas Hoenger1
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1 European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
2 Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216, USA
To whom correspondence should be addressed
Andreas Hoenger Tel: +49 6221 387453; Fax: +49 6221 387519; hoenger@embl-heidelberg.de
Received 1 April 2003; Accepted 20 May 2003; Published online 1 July 2003.
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Abstract
We have analysed the structural and physical properties of the carboxy-terminal stalk region of a kinesin-II, Xenopus kinesin-like protein 3A/B (Xklp3A/B), which we showed to be essential for heterodimerization in a previous work (De Marco et al., 2001). We expressed the corresponding A-stalk and B-stalk fragments and investigated their modes of interaction by analytical ultracentrifugation (AUC), circular dichroism spectroscopy, denaturation assays and electron microscopy. Co-expression of the A-stalk and B-stalk produced the properly folded, hetero-dimeric coiled coil at high yields. The dimeric nature of the complex was confirmed by AUC. We also found that the isolated A-stalk fragment forms a stable helix by itself and shows a significant tendency towards homodimer and higher-order complex formation. In the absence of the corresponding A-stalk fragment, the isolated B-stalk fragment remains partially unfolded, which suggests that the A-stalk provides a template structure for the B-stalk in order to recompose the complete heterodimeric coiled coil.
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