Premium
Effect of an added spacer on the ‘double lockdown’ inhibition of kinesin‐1 by tail domains
Author(s) -
Hackney David Daniel,
Yeo Young Woon
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.558.11
Subject(s) - kinesin , biophysics , coiled coil , microtubule , folding (dsp implementation) , linker , chemistry , atp hydrolysis , dimer , crystallography , amino acid , stereochemistry , biochemistry , biology , atpase , microbiology and biotechnology , enzyme , computer science , engineering , organic chemistry , electrical engineering , operating system
Kinesin‐1 is a motor protein that produces processive movement along microtubules using the energy of ATP hydrolysis. Under physiological conditions, kinesin‐1 is autoinhibited by folding at a central hinge to allow the tail domains to bind to the head (motor) domains. Even though both the tails and heads are dimeric, inhibition is produced by binding of only one tail domain to a dimer of heads. The recent determination of the structure of a head‐tail complex by X‐ray crystallography (Kaan, et al., Science 333 , 832 (2011)) indicated that a single tail domain formed a bridge between two head domains, effectively cross‐linking them. This suggested a ‘double lockdown’ mechanism in which ADP release is inhibited because the coupled undocking of the neck linker cannot occur while maintaining both the cross link between heads at the coiled‐coil neck and the new cross link provided by the tail domain. Insertion of flexible spacers at the start of the coiled‐coil domain should allow greater relative movement of the two head domains and make it more difficult for tails to tie them down with an additional cross link. We have tested a series of single amino acid substitutions and inserts and deletions and find only small differences in the affinity of tails. Long spacers of 6 and 12 amino acids, however, decrease affinity of heads for tails by 13 and 34‐fold respectively. Supported by NIH grant 1R01NS058848.