BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:iCalendar-Ruby BEGIN:VEVENT CATEGORIES:Lectures & Presentations DESCRIPTION:Chemistry & Biochemistry Colloquium | Justin Holub\, April 17\n \n \n\n\n\nThe Chemistry & Biochemistry colloquium series presents Justin H olub discussing "Monitoring ligand-mediated helix 12 transitions within the human estrogen receptor α using bipartite tetracysteine display" on April 17 from 4:10 to 5:05 p.m. in Walter 135.\n\n \n\nHolub is Associate Profess or of Chemistry and Biochemistry at Ohio University. The host is Eric Masso n.\n\n \n\nABSTRACT: Strategies that inform on protein structural dynamics in native environments greatly enhance our understanding of protein functio n and can facilitate the development of new therapies to treat disease. The human estrogen receptor a (ERa) is a ligand-mediated transcription factor that is modulated by the natural steroid hormone 17b-estradiol (E2). Struct urally\, the ERa ligand-binding domain (ERa-LBD) adopts a well-folded globu lar structure comprised of 11 a-helices and a short b-strand. The globular portion of the ERa-LBD is believed to be relatively static\; however\, the C-terminal helix 12 (H12) is dynamic and can adopt different configurations depending on what ligand occupies the LBD. In this study\, we applied fluo rescent labeling coupled with bipartite tetracysteine display to surveil li gand-mediated helix H12 transitions within the ERa-LBD. Wild-type ERa-LBDs were mutated to express a tetracysteine (C4) motif that binds to a biarseni cal pro-fluorescent dye (FlAsH) upon transition of H12 to a folded state. I nterestingly\, binding of an agonist was accompanied by a reduction in FlAs H fluorescence\, indicating that the C4 motif becomes occluded when H12 is tightly associated with the LBD. Our results also indicate that H12 remains flexible in unliganded receptors and receptors bound to pure antagonists\, allowing for significant increases in FlAsH fluorescence. Such observation s made it possible to determine association rates and equilibrium binding c onstants for FlAsH to the ERa-LBD in the presence and absence of estrogenic ligands. We anticipate that this genetically-encodable assay will be usefu l for studying how estrogenic compounds influence structural organization o f the ERa-LBD and may be applied to studying helix transitions within other members of the nuclear receptor superfamily.\n\n \n\nRef: R. Pokhrel\, T. Tang\, J. M. Holub. Org Biomol Chem.\, 2020\, 18\, 6063-71 DTEND:20230417T210500Z DTSTAMP:20241122T230500Z DTSTART:20230417T201000Z GEO:39.322732;-82.10287 LOCATION:Walter Hall\, 145 SEQUENCE:0 SUMMARY:Chemistry & Biochemistry Colloquium | Monitoring ligand-mediated he lix 12 transitions within the human estrogen receptor α using bipartite tet racysteine display\, April 17 UID:tag:localist.com\,2008:EventInstance_42582831868996 URL:https://calendar.ohio.edu/event/chemistry_biochemistry_colloquium_april _17_2023 END:VEVENT END:VCALENDAR