The applications of laser spectroscopy in analytical chemistry and biochemistry: investigating the photophysics of hypericin and hypocrellin, as well as the structure of porcine fructose-1,6-bisphosphatase

dc.contributor.advisor Jacob W. Petrich
dc.contributor.author Wen, Jin
dc.contributor.department Chemistry
dc.date 2018-08-24T18:54:48.000
dc.date.accessioned 2020-07-02T05:45:15Z
dc.date.available 2020-07-02T05:45:15Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2002
dc.date.issued 2002-01-01
dc.description.abstract <p>This dissertation addresses the applications of ultrafast laser spectroscopy in investigating the photophysical properties of hypericin, hypocrellin and their analogs, as well as the structure of protein.;Hypericin and hypocrellin are naturally occurring photosensitizers. The attractions of those compounds are their light induced antiviral and antitumor activities. A variety of techniques, i.e. time-resolved single photon counting, pump-probe experiment and fluorescence upconversion, are utilized to reveal the photophysical properties of hypericin, hypocrellin and their analogs. The primary photoprocess is excited-state H-atom transfer that has been partially attributed to the virucidal activity of hypericin.;Comparison of the excited-state H-atom transfer in hypocrellin A and B, by using time-resolved absorption and fluorescence upconversion techniques, as well as ab initio quantum mechanical calculations, suggests that excited-state conformation change are coupled to the H-atom transfer reaction. A simple model is employed to describe the photophysics of hypocrellin B.;The synthesis of a molecule containing hypericin and luciferin moieties joined by a tether is reported. This hypericin-luciferin tethered molecule exhibits excited-state behavior that is very similar to that of its parent compounds and antiviral activity that is identical, within experimental error, to that of its most closely related parent compound, pseudohypericin. The implications of the chemiluminescent reaction with luciferin and luciferase as an alterative light source for photodynamic therapy are discussed.;Time-resolved fluorescence and direct mutation are employed to study the environment of Trp57 in the dynamic loop of porcine liver fructose-1,6-bisphosphatase (FBPase). The studies indicate that Trp 57 in R-state conformer is in the hydrophobic pocket and Trp 57 in T-state conformer is exposed to the solvent, which is consistent with the predictions made on the basis of X-ray crystal structures of Trp 57 FBPase. The unexpected red shift in steady-state fluorescence of Trp57 in R-state relative to that in T-state is attributed in part to the electrostatic perturbation of the Asp127.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/489/
dc.identifier.articleid 1488
dc.identifier.contextkey 6074927
dc.identifier.doi https://doi.org/10.31274/rtd-180813-12115
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/489
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/77573
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/489/r_3061874.pdf|||Sat Jan 15 00:28:49 UTC 2022
dc.subject.disciplines Analytical Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Analytical chemistry
dc.title The applications of laser spectroscopy in analytical chemistry and biochemistry: investigating the photophysics of hypericin and hypocrellin, as well as the structure of porcine fructose-1,6-bisphosphatase
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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