Domain analysis of the tubulin cofactor system: a model for tubulin folding and dimerization.
BACKGROUND
The correct folding and dimerization of tubulins, before their addition to the microtubular structure, needs a group of conserved proteins called cofactors A to E. The biochemical analysis of cofactors gave an insight to their general functions, however not much is known about the domain structure and detailed, molecular function of these proteins.


RESULTS
Combining modelling and fold prediction tools, we present 3D models of all cofactors, including several previously unannotated domains of cofactors B-E. Apart from the new HEAT and Armadillo domains in cofactor D and an unusual spectrin-like domain in cofactor C, we have identified a new subfamily of ubiquitin-like domains in cofactors B and E. Together, these observations provide a reliable, molecular level model of cofactor complex.


CONCLUSIONS
Distant homology searches allowed the identification of unknown regions of cofactors as self-reliant domains and allow us to present a detailed hypothesis of how a cofactor complex performs its function.
Grynberg
Marcin
M
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St, 02-106 Warsaw, Poland. marcin@ljcrf.edu
Jaroszewski
Lukasz
L
Godzik
Adam
A
D000595:Amino Acid Sequence; D000818:Animals; D002107:Caenorhabditis / Q000737:chemistry; D002347:Carps; D019281:Dimerization; D029941:Fish Proteins / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry; D015801:Helminth Proteins / Q000737:chemistry; D006801:Humans; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011237:Predictive Value of Tests; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011817:Rabbits; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000737:chemistry*
D029941:Fish Proteins; D005656:Fungal Proteins; D015801:Helminth Proteins; D018832:Molecular Chaperones; D010455:Peptides; D029702:Schizosaccharomyces pombe Proteins; D014404:Tubulin; C455270:tubulin-specific chaperone C