Linked Life Data

7760939

Source:http://linkedlifedata.com/resource/pubmed/id/7760939

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6530
pubmed:dateCreated
1995-6-23
pubmed:abstractText
Tubulin, the major component of microtubules, is a heterodimer of two chains, alpha and beta, both of relative molecular mass 50,000 (Mr50K) and with 40-50% identity. The isotypic variety and conformational flexibility of tubulin have so far made it impossible to obtain crystals for X-ray work. Structural knowledge of tubulin has been limited to about 20 A from X-ray diffraction of oriented microtubules, and from electron microscopy of microtubules and zinc-induced crystalline sheets in negative stain. The sheets consist of protofilaments similar to those in microtubules but associated in an antiparallel arrangement, and their two-dimensional character is ideal for high-resolution electron microscopy. Here we present a three-dimensional reconstruction of tubulin to 6.5 A resolution, obtained by electron crystallography of zinc-induced two-dimensional crystals of the protein. The alpha- and beta-subunits appear topologically similar, in agreement with their sequence homology. Several features can be defined in terms of secondary structure. An apparent alpha-helical portion, adjacent to both interdimer and inter-protofilament contacts, is tentatively attributed to a segment near the carboxy terminus of the protein. We can assign the alpha- and beta-subunits on the basis of projection studies of the binding of taxol, which show one taxol site per tubulin heterodimer, in agreement with the known stoichiometry of taxol in microtubules. These studies indicate that taxol affects the interaction between protofilaments; to our knowledge, this is the first time that a ligand-binding site has been visualized in the tubulin molecule.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
375
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
424-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Structure of tubulin at 6.5 A and location of the taxol-binding site.
pubmed:affiliation
Life Science Division, Lawrence Berkeley Laboratory, California 94720, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't