Characterizing the Epothilone Binding Site on β-Tubulin by Photoaffinity Labeling: Identification of β-Tubulin Peptides TARGSQQY and TSRGSQQY as Targets of an Epothilone Photoprobe for Polymerized Tubulin.
Characterizing the Epothilone Binding Site on β-Tubulin by Photoaffinity Labeling: Identification of β-Tubulin Peptides TARGSQQY and TSRGSQQY as Targets of an Epothilone Photoprobe for Polymerized Tubulin.
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DOI：
10.1021/acs.jmedchem.6b00188
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发表时间：
2016-04-14
影响因子：
7.3
通讯作者：
Georg GI
中科院分区：
文献类型：
--
作者：
Ranade AR;Higgins L;Markowski TW;Glaser N;Kashin D;Bai R;Hong KH;Hamel E;Höfle G;Georg GI
用埃坡霉素A光探针进行光亲和标记，鉴定出β-微管蛋白肽TARGSQQY和TSRGSQQY作为聚合微管蛋白的光探针的靶标。这些肽代表不同β-微管蛋白同种型中的残基274 - 281。将光探针的产生卡宾的21-重氮/三唑部分放置在TBB3同源模型中的TARGSQQY肽附近，预测了光探针的结合位姿和构象，其非常类似于1）埃博霉素A与α，β-微管蛋白复合物和2）二聚体和聚合微管蛋白的饱和转移差NMR和转移NOESY NMR研究。因此，我们的研究结果为这些模型提供了额外的支持，这些模型在生理上是已经提出的埃博霉素A在β-微管蛋白的紫杉烷口袋中的几种结合模式中最相关的。
Photoaffinity labeling with an epothilone A photoprobe led to the identification of the β-tubulin peptides TARGSQQY and TSRGSQQY as targets of the photoprobe for polymerized tubulin. These peptides represent residues 274–281 in different β-tubulin isotypes. Placing the carbene producing 21-diazo/triazolo moiety of the photoprobe in the vicinity of the TARGSQQY peptide in a homology model of TBB3 predicted a binding pose and conformation of the photoprobe that are very similar to the ones reported for 1) the high resolution cocrystal structure of epothilone A with an α,β-tubulin complex and for 2) a saturation transfer difference NMR and transferred NOESY NMR study of dimeric and polymerized tubulin. Our findings thus provide additional support for these models as physiologically the most relevant among several modes of binding that have been proposed for epothilone A in the taxane pocket of β-tubulin.