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dc.contributor.authorHillpot, Eric C
dc.date.accessioned2019-10-15T16:51:14Z
dc.date.available2019-10-15T16:51:14Z
dc.date.issued2019-08-30
dc.identifier.otherHillpot_cornell_0058O_10702
dc.identifier.otherhttp://dissertations.umi.com/cornell:10702
dc.identifier.otherbibid: 11050736
dc.identifier.urihttps://hdl.handle.net/1813/67750
dc.description.abstractG protein coupled receptors play important roles in cellular signaling and are stimulated by a multitude of extracellular signals. These proteins initiate signal transduction cascades that elicit a variety of cellular responses. Once activated, G protein coupled receptors activate G proteins which further stimulate target proteins to elicit cellular responses such as enzyme activity, translation and ion channels60. In this study, we set out to solve the crystal structure of a constitutively active form of the alpha subunit of the retinal G protein, transducin. This activated G protein, designated as αT* SFD QLRC, elicits the ability to stimulate its effector molecule, PDE, to levels comparable to activated native retinal alpha. Crystals of αT* SFD QLRC were grown and x-ray diffraction data sets were observed at low resolution. Following insights from a recent paper by Hu et al, 2018, a C210S mutant was created to help improve diffraction. Data sets of αT* SFD QLRC C210S were collected to 2.8 Å and compared to previously solved GDP-bound (1TAG) and GTPγS-bound (1TND) native αT subunits. The crystal structure of αT* SFD QLRC C210S reveals that despite being fully active in vitro, GDP, and not GTP, is bound in the structure. As a result, Switch II and Switch III appear to be in a transition state between the inactive GDP-bound state and the active GTP-bound state and are un-modelled due to low electron density. Future work involves improving crystallization of αT* SFD QLRC C210S to obtain a GTP-bound structure so that the structure can be used to elucidate the mechanism by which the transducin α subunit, especially the phenylalanine residue of the SFD mutation, confers maximum PDE activity.
dc.language.isoen_US
dc.subjectTransducin
dc.subjectCellular biology
dc.subjectG protein coupled receptor
dc.subjectG proteins
dc.subjectSignaling
dc.subjectvision
dc.subjectx-ray crystallography
dc.subjectBiology
dc.subjectBiochemistry
dc.titleTHE 2.8 Å CRYSTAL STRUCTURE OF A CONSTITUTIVELY ACTIVE ALPHA TRANSDUCIN SUBUNIT
dc.typedissertation or thesis
thesis.degree.disciplineChemistry and Chemical Biology
thesis.degree.grantorCornell University
thesis.degree.levelMaster of Science
thesis.degree.nameM.S., Chemistry and Chemical Biology
dc.contributor.chairZax, David B.
dc.contributor.committeeMemberDavis, Harry Floyd
dcterms.licensehttps://hdl.handle.net/1813/59810
dc.identifier.doihttps://doi.org/10.7298/hd0h-r243


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