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J Struct Biol. 1998;122(1-2):30-41.

The coiled-coil helix in the neck of kinesin.

Author information

1
Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, Hamburg, D-22603, Germany.

Abstract

Kinesin is a microtubule-dependent motor protein. We have recently determined the X-ray structure of monomeric and dimeric kinesin from rat brain. The dimer consists of two motor domains, held together by their alpha-helical neck domains forming a coiled coil. Here we analyze the nature of the interactions in the neck domain (residues 339-370). Overall, the neck helix shows a heptad repeat (abcdefg)n typical of coiled coils, with mostly nonpolar residues in positions a and d. However, the first segment (339-355) contains several nonclassical residues in the a and d positions which tend to weaken the hydrophobic interaction along the common interface. Instead, stabilization is achieved by a hydrophobic "coat" formed by the a and d residues and the long aliphatic moieties of lysines and glutamates, extending away from the coiled-coil core. By contrast, the second segment of the kinesin neck (356-370) shows a classical leucine zipper pattern in which most of the hydrophobic residues are buried at the highly symmetrical dimer interface. The end of the neck reveals the structure of a potential coiled-coil "trigger" sequence.

PMID:
9724604
DOI:
10.1006/jsbi.1998.3986
[Indexed for MEDLINE]

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