The overall conformation of conventional kinesins studied by small angle X-ray and neutron scattering

The quaternary structures of several monomeric and dimeric kinesin construc ts from Homo sapiens and Drosophila melanogaster were analyzed using small angle K-ray and neutron scattering. The experimental scattering curves of t hese proteins were compared with simulated scattering curves calculated fro m available crystallographic coordinates. These comparisons indicate that t he overall conformations of the solution structures of D. melanogaster and H. sapiens kinesin heavy chain dimers are compatible with the crystal struc ture of dimeric kinesin from Rattus norvegicus. This suggests that the unus ual asymmetric conformation of dimeric kinesin in the microtubule-independe nt ADP state is likely to be a general feature of the kinesin heavy chain s ubfamily. An intermediate length Drosophila construct (365 residues) is mos tly monomeric at low protein concentration whereas at higher concentrations it is dimeric with a tendency to form higher oligomers.