High-resolution model of the microtubule.
A high-resolution model of the microtubule has been obtained by docking the crystal structure of tubulin into a 20 A map of the microtubule. The excellent fit indicates the similarity of the tubulin conformation in both polymers and defines the orientation of the tubulin structure within the microtubule. Long C-terminal helices form the crest on the outside of the protofilament, while long loops define the microtubule lumen. The exchangeable nucleotide in beta-tubulin is exposed at the plus end of the microtubule, while the proposed catalytic residue in alpha-tubulin is exposed at the minus end. Extensive longitudinal interfaces between monomers have polar and hydrophobic components. At the lateral contacts, a nucleotide-sensitive helix interacts with a loop that contributes to the binding site of taxol in beta-tubulin.
Nogales
E
E
Lawrence Berkeley National Laboratory, Molecular and Cell Biology Department, University of California at Berkeley, California 94720, USA. enogales@lbl.gov
Whittaker
M
M
Milligan
R A
RA
Downing
K H
KH
D018360:Crystallography, X-Ray; D008870:Microtubules / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D014404:Tubulin / Q000737:chemistry*