title: 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.
abstract: 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.
authors.affiliation: Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, University of Minnesota , 717 Delaware Street, SE, Minneapolis, Minnesota 55414, United States.
authors.forename: Adwait R
authors.initials: AR
authors.lastname: Ranade
authors.affiliation: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , 321 Church Street, SE, Minneapolis, Minnesota 55455, United States.
authors.forename: LeeAnn
authors.initials: L
authors.lastname: Higgins
authors.affiliation: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , 321 Church Street, SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Todd W
authors.initials: TW
authors.lastname: Markowski
authors.affiliation: Department of Natural Product Chemistry, Helmholtz Center for Infection Research , Inhoffenstrasse 7, 38124 Braunschweig, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Glaser
authors.affiliation: Department of Natural Product Chemistry, Helmholtz Center for Infection Research , Inhoffenstrasse 7, 38124 Braunschweig, Germany.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Kashin
authors.affiliation: Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States.
authors.forename: Ruoli
authors.initials: R
authors.lastname: Bai
authors.affiliation: Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, University of Minnesota , 717 Delaware Street, SE, Minneapolis, Minnesota 55414, United States.
authors.forename: Kwon Ho
authors.initials: KH
authors.lastname: Hong
authors.affiliation: Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States.
authors.forename: Ernest
authors.initials: E
authors.lastname: Hamel
authors.affiliation: Department of Natural Product Chemistry, Helmholtz Center for Infection Research , Inhoffenstrasse 7, 38124 Braunschweig, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Höfle
authors.affiliation: Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, University of Minnesota , 717 Delaware Street, SE, Minneapolis, Minnesota 55414, United States.
authors.forename: Gunda I
authors.initials: GI
authors.lastname: Georg
mesh_terms: D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002417:Cattle; D018360:Crystallography, X-Ray; D019008:Drug Resistance, Neoplasm; D034261:Epothilones / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006801:Humans; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D015335:Molecular Probes / Q000737:chemistry*; D010051:Ovarian Neoplasms / Q000737:chemistry / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry*; D019920:Photoaffinity Labels / Q000737:chemistry*; D058105:Polymerization; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism; D050257:Tubulin Modulators / Q000737:chemistry*; D014407:Tumor Cells, Cultured
chemical_list: D034261:Epothilones; D015335:Molecular Probes; D010446:Peptide Fragments; D019920:Photoaffinity Labels; D014404:Tubulin; D050257:Tubulin Modulators; C093787:epothilone A