title: Discovery and characterization of the laulimalide-microtubule binding mode by mass shift perturbation mapping.
abstract: Conventional approaches to site mapping have so far failed to identify the laulimalide binding site on microtubules. Using mass shift perturbation analysis and data-directed docking, we demonstrate that laulimalide binds to the exterior of the microtubule on beta-tubulin, in a region previously unknown to support ligand binding and well removed from the paclitaxel site. Shift maps for docetaxel and laulimalide are otherwise identical, indicating a common state of microtubule stability induced by occupancy of the distinct sites. The preferred binding mode highlights the penetration of the laulimalide side chain into a deep, narrow cavity through a unique conformation not strongly populated in solution, akin to a "striking cobra." This mode supports the development of a pharmacophore model and reveals the importance of the C1-C15 axis in the macrocycle.
authors.affiliation: University of Calgary, Department of Biochemistry and Molecular Biology, 3330 Hospital Drive NW, Calgary, AB T2N4N1, Canada.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Bennett
authors.forename: Khaled
authors.initials: K
authors.lastname: Barakat
authors.forename: J Torin
authors.initials: JT
authors.lastname: Huzil
authors.forename: Jack
authors.initials: J
authors.lastname: Tuszynski
authors.forename: David C
authors.initials: DC
authors.lastname: Schriemer
mesh_terms: D000494:Allosteric Regulation; D000577:Amides / Q000737:chemistry; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D041961:Deuterium Exchange Measurement; D008024:Ligands; D018942:Macrolides / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods*; D008870:Microtubules / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation
chemical_list: D000577:Amides; D000970:Antineoplastic Agents; D008024:Ligands; D018942:Macrolides; C117305:laulimalide