A conserved tyrosine in the neck of a fungal kinesin regulates the catalytic motor core.
The neck domain of fungal conventional kinesins displays characteristic properties which are reflected in a specific sequence pattern. The exchange of the strictly conserved Tyr 362, not present in animals, into Lys, Cys or Phe leads to a failure to dimerize. The destabilizing effect is confirmed by a lower coiled-coil propensity of mutant peptides. Whereas the Phe substitution has only a structural effect, the Lys and Cys replacements lead to dramatic kinetic changes. The steady state ATPase is 4- to 7-fold accelerated, which may be due to a faster microtubule-stimulated ADP release rate. These data suggest that an inhibitory effect of the fungal neck domain on the motor core is mediated by direct interaction of the aromatic ring of Tyr 362 with the head, whereas the OH group is essential for dimerization. This is the first demonstration of a direct influence of the kinesin neck region in regulation of the catalytic activity.
Schäfer
Friederike
F
Adolf Butenandt Institute, Cell Biology, University of Munich, Schillerstrasse 42, D-80336 Munich, Germany.
Deluca
Dominga
D
Majdic
Ulrike
U
Kirchner
Joachim
J
Schliwa
Manfred
M
Moroder
Luis
L
Woehlke
Günther
G
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D019281:Dimerization; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D011487:Protein Conformation; D016415:Sequence Alignment; D014443:Tyrosine / Q000378:metabolism*
D005656:Fungal Proteins; D020409:Molecular Motor Proteins; D010455:Peptides; D014443:Tyrosine; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D016547:Kinesins