RT Journal Article SR Electronic T1 Structural Insights into the Pharmacophore of Vinca Domain Inhibitors of Microtubules JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP mol.115.100149 DO 10.1124/mol.115.100149 A1 Yuxi Wang A1 Benz W. Frederick, Sr. A1 Yangping Wu, Sr. A1 Qisheng Wang A1 Yunfeng Chen A1 Xiangzheng Chen A1 Huiyan Li A1 Yonghui Zhang A1 Rundong Zhang A1 Jinliang Yang YR 2015 UL http://molpharm.aspetjournals.org/content/early/2015/12/09/mol.115.100149.abstract AB Antibody-drug conjugates (ADCs) have achieved great success in cancer therapy in recent years. Some peptidyl microtubule inhibitors consisting of natural and unnatural amino acids, such as MMAE and MMAF, are extremely cytotoxic and have been used as a payload in ADCs. However, their precise molecular interaction with tubulin and microtubules remains unclear. We determined the crystal structures of tubulin in complex with three ultra-potent peptidyl microtubule inhibitors, MMAE, HTI-286 and tubulysin M at 2.5Å. Our data showed that the three peptides bound to the vinca domain and shared a common and key pharmacophore containing two consecutive hydrophobic groups (Val, Ile-like side chain). These groups protruded in opposite directions into hydrophobic pockets on the tubulin β and α subunits. Nitrogen and oxygen atoms from the same backbone formed hydrogen bonds with Asn329 from the α subunit and Asp179 from the β subunit in a direction normal to the surface formed by the above hydrophobic groups. In addition, our crystal structure data indicated that tubulysin M bound to the β subunit alone providing a structural explanation for its higher affinity. We also compared the conformations of two representative structurally different vinca domain compounds ustiloxin D and vinblastine with those of the above peptidyl ligands, and found that they shared a similar pharmacophore. Our findings lay a foundation for the rational design of novel vinca domain ligands and may facilitate the development of microtubule inhibitors with high specificity, affinity and efficiency as payloads for ADCs in cancer therapy.