1tub
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TUBULIN ALPHA-BETA DIMER, ELECTRON DIFFRACTION
OverviewOverview
The alphabeta tubulin heterodimer is the structural subunit of, microtubules, which are cytoskeletal elements that are essential for, intracellular transport and cell division in all eukaryotes. Each tubulin, monomer binds a guanine nucleotide, which is nonexchangeable when it is, bound in the alpha subunit, or N site, and exchangeable when bound in the, beta subunit, or E site. The alpha- and beta-tubulins share 40% amino-acid, sequence identity, both exist in several isotype forms, and both undergo a, variety of posttranslational modifications. Limited sequence homology has, been found with the proteins FtsZ and Misato, which are involved in cell, division in bacteria and Drosophila, respectively. Here we present an, atomic model of the alphabeta tubulin dimer fitted to a 3.7-A density map, obtained by electron crystallography of zinc-induced tubulin sheets. The, structures of alpha- and beta-tubulin are basically identical: each, monomer is formed by a core of two beta-sheets surrounded by, alpha-helices. The monomer structure is very compact, but can be divided, into three functional domains: the amino-terminal domain containing the, nucleotide-binding region, an intermediate domain containing the, Taxol-binding site, and the carboxy-terminal domain, which probably, constitutes the binding surface for motor proteins.
About this StructureAbout this Structure
1TUB is a Protein complex structure of sequences from Sus scrofa with GTP, GDP and TXL as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the alpha beta tubulin dimer by electron crystallography., Nogales E, Wolf SG, Downing KH, Nature. 1998 Jan 8;391(6663):199-203. PMID:9428769
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