Abstract
Tubulin, the major component of microtubules, has a tendency to lose its ability to assemble or to bind to ligands in a time-dependent process known as 'decay'. The decay process also causes tubulin to expose sulfhydryl groups and hydrophobic areas. The antimitotic drug phomopsin A strongly protects the tubulin molecule from decay. Here we have studied the interaction of phomopsin A with αβ tubulin and tubulin which has been treated with subtilisin to remove selectively the C-termini of the α and β chains (α(s)β(s)). The binding of phomopsin A to αβ tubulin decreases the sulfhydryl titer by approximately 1.0 mol/mol. Selective removal of the peptides from the C-terminal ends does not affect phomopsin A's interaction with tubulin. Moreover, the α(s)β(s) tubulin-phomopsin A complex appears to be more stable than the αβ tubulin-phomopsin A complex as determined by the time-dependent increase in exposure of sulfhydryl groups and hydrophobic areas on tubulin. In fact, phomopsin A inhibits the decay process of α(s)β(s) tubulin completely. This observation raises the possibility of determining the conformation of this configuration of tubulin.
Original language | English (US) |
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Pages (from-to) | 99-105 |
Number of pages | 7 |
Journal | Journal of Protein Chemistry |
Volume | 16 |
Issue number | 2 |
DOIs | |
State | Published - 1997 |
Keywords
- C-terminal domain
- Tubulin
- alkylation
- hydrophobic areas
- phomopsin A
ASJC Scopus subject areas
- Biochemistry