1JFF

Refined structure of alpha-beta tubulin from zinc-induced sheets stabilized with taxol

Summary for 1JFF

• Entry DOI: 10.2210/pdb1jff/pdb
• Related: 1TUB
• Descriptor: tubulin alpha chain, tubulin beta chain, ZINC ION, ... (7 entities in total)
• Functional Keywords: dimer, gtpase, structural protein
• Biological source: Bos taurus (cattle); More
• Total number of polymer chains: 2
• Total formula weight: 101925.01

Authors

Lowe, J.,Li, H.,Downing, K.H.,Nogales, E. (deposition date: 2001-06-20, release date: 2001-09-19, Last modification date: 2023-08-16)

Primary citation

Lowe, J.,Li, H.,Downing, K.H.,Nogales, E.
Refined structure of alpha beta-tubulin at 3.5 A resolution.
J.Mol.Biol., 313:1045-1057, 2001

PubMed Abstract: We present a refined model of the alpha beta-tubulin dimer to 3.5 A resolution. An improved experimental density for the zinc-induced tubulin sheets was obtained by adding 114 electron diffraction patterns at 40-60 degrees tilt and increasing the completeness of structure factor amplitudes to 84.7 %. The refined structure was obtained using maximum-likelihood including phase information from experimental images, and simulated annealing Cartesian refinement to an R-factor of 23.2 and free R-factor of 29.7. The current model includes residues alpha:2-34, alpha:61-439, beta:2-437, one molecule of GTP, one of GDP, and one of taxol, as well as one magnesium ion at the non-exchangeable nucleotide site, and one putative zinc ion near the M-loop in the alpha-tubulin subunit. The acidic C-terminal tails could not be traced accurately, neither could the N-terminal loop including residues 35-60 in the alpha-subunit. There are no major changes in the overall fold of tubulin with respect to the previous structure, testifying to the quality of the initial experimental phases. The overall geometry of the model is, however, greatly improved, and the position of side-chains, especially those of exposed polar/charged groups, is much better defined. Three short protein sequence frame shifts were detected with respect to the non-refined structure. In light of the new model we discuss details of the tubulin structure such as nucleotide and taxol binding sites, lateral contacts in zinc-sheets, and the significance of the location of highly conserved residues.

PubMed: 11700061
DOI: 10.1006/jmbi.2001.5077

Experimental method

ELECTRON CRYSTALLOGRAPHY (3.5 Å)