Ashutosh S Jogalekar, Krishnan Damodaran, Frederik H Kriel, Won-Hyuk Jung, Ana A Alcaraz, Shi Zhong, Dennis P Curran, James P Snyder
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Journal of the American Chemical Society 2011 Mar 2Dictyostatin (DCT, 1) is a complex, flexible polyketide macrolide that demonstrates potent microtubule-polymerization activity. Both a solution structure (2a) and a possible binding mode for DCT (Conf-1) have been proposed by earlier NMR experiments. In the present study, the conformational landscape of DCT in DMSO-d(6) and methanol-d(4) was explored using extensive force-field-based conformational searches combined with geometric parameters derived from solution NMR data. The results portray a diversity of conformations for dictyostatin that illustrates the molecule's flexibility and excludes the previously suggested dominant solution conformation 2a. One conformation present in DMSO-d(6) with a 7% population (Conf-2, 0.6 kcal/mol above the global minimum at 298°) also satisfies the TR-NOESY NMR parameters of Canales et al. that characterize the taxane binding-site interaction between DCT and assembled microtubules in water. Application of several docking methods (Glide, Autodock, and RosettaLigand) has identified a low-energy binding model of the DCT/β-tubulin complex (Pose-2/Conf-2) that is gratifyingly compatible with the emerging DCT structure-activity data.
Ashutosh S Jogalekar, Krishnan Damodaran, Frederik H Kriel, Won-Hyuk Jung, Ana A Alcaraz, Shi Zhong, Dennis P Curran, James P Snyder. Dictyostatin flexibility bridges conformations in solution and in the β-tubulin taxane binding site. Journal of the American Chemical Society. 2011 Mar 2;133(8):2427-36
PMID: 21299225
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