A kinesin-like mechanoenzyme from the zygomycete Syncephalastrum racemosum shares biochemical similarities with conventional kinesin from Neurospora crassa.
The kinesin superfamily consists of mechanoenzymes that convert chemical energy, stored in nucleoside triphosphates, into movement along microtubules. The founding member of this protein superfamily, the so-called conventional kinesin, was only known from animal sources until the recent description of kinesin from the filamentous fungus Neurospora crassa (G. Steinberg, M. Schliwa, Mol. Biol. Cell 6, 1605-1618 (1995)). To determine whether similar motors with comparable features are common in other filamentous fungi, a kinesin from a zygomycete, Syncephalastrum racemosum, was purified. Here, the isolation and characterization of this motorenzyme is described. The purified protein consisted of a doublet at 112 kDa and 115 kDa with no additional polypeptides. This was consistent with a calculated molecular mass of approximately 240 kDa and suggests that the motor is a dimer with a more globular shape than conventional kinesin from animal sources. In gliding assays the enzyme moved microtubules at 2.5 to 3.4 microns/s and had a nucleotide specificity similar to the Neurospora kinesin motor. Peptide antibodies against conserved regions in the head and the tall domain of conventional kinesins cross-reacted with the Syncephalastrum motor. In vitro, the enzyme was able to drive the microtubule-dependent movement of vesicles isolated from Syncephalastrum racemosum, as well as Neurospora crassa, and Aspergillus nidulans. In summary, the Syncephalastrum motor has many of the unique features in common with the conventional kinesin from the ascomycete Neurospora crassa and probably shares a similar function in living hyphae.
Steinberg
G
G
Institute for Cell Biology, Ludwig-Maximilians-University, München/Germany.
D000818:Animals; D001693:Biological Transport, Active; D003429:Cross Reactions; D019281:Dimerization; D066298:In Vitro Techniques; D016547:Kinesins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D008870:Microtubules / Q000201:enzymology / Q000502:physiology; D008970:Molecular Weight; D009068:Movement; D009090:Mucorales / Q000201:enzymology* / Q000502:physiology; D009492:Neurospora crassa / Q000201:enzymology* / Q000502:physiology; D013045:Species Specificity
D016547:Kinesins