Anomalous phosphorescence decays arising from the interaction of tryptophan side chain with proximal disulfide linkages are investigated with a number of proteins in rigid media at 77K. Changes in the lifetime of the fast, or anomalous, component provide evidence for subtle ligand-induced conformational changes with both an anti-galactan antibody and the enzyme lysozyme. The induced changes are seen to occur both directly at, and at a distance from, the combining sites. Recognition of the disulfide interaction is used to rationalize earlier fluorescence results with these systems. / The distance dependence of the tryptophan-disulfide interaction at the triplet level is established through a time-dependent phosphorescence study of a model system. The interaction is shown to fall off exponentially with separation, so that measured variations in the anomalous decays can detect geometrical changes of much less than one angstrom. / Temperature-dependent studies of the tryptophan-disulfide interaction with both proteins and the model system are described. The evidence obtained suggests that the disulfide perturbation of the triplet state of tryptophan occurs as a result of a photo-induced one-electron transfer. / The steep distance dependence of the interaction and the utility of these decays in revealing conformational heterogeneity is demonstrated from the non-exponential behavior of several single tryptophan-containing proteins and peptides.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74586 |
| Date | January 1990 |
| Creators | Li, Zhi, 1959- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001170437, proquestno: AAINN66550, Theses scanned by UMI/ProQuest. |
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