The paclitaxel site in tubulin probed by site-directed mutagenesis of Saccharomyces cerevisiae beta-tubulin.
Previously, we created a paclitaxel-sensitive strain of Saccharomyces cerevisiae by mutating five amino acid residues in beta-tubulin in a strain that has a decreased level of the ABC multidrug transporters. We have used site-directed mutagenesis to examine the relative importance of the five residues in determining sensitivity of this strain to paclitaxel. We found that the change at position 19 from K (brain beta-tubulin) to A (yeast beta-tubulin) and at position 227 from H (brain beta-tubulin) to N (yeast beta-tubulin) had no effect on the activity of paclitaxel. On the other hand, the changes V23T, D26G and F270Y, drastically reduced sensitivity of AD1-8-tax to paclitaxel. Molecular modeling and computational studies were used to explain the results.
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045-7534, USA.
Ruth A
RA
Entwistle
Robert D
RD
Winefield
Travis B
TB
Foland
Gerald H
GH
Lushington
Richard H
RH
Himes
D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000633:toxicity; D001542:Benomyl / Q000494:pharmacology; D001665:Binding Sites; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017239:Paclitaxel / Q000737:chemistry* / Q000633:toxicity; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics; D014404:Tubulin / Q000737:chemistry* / Q000235:genetics; D050257:Tubulin Modulators / Q000737:chemistry* / Q000633:toxicity
D000972:Antineoplastic Agents, Phytogenic; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin; D050257:Tubulin Modulators; D017239:Paclitaxel; D001542:Benomyl