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Model studies of the cub-histidine-tyrosine centre in cytochrome c oxidase
Model studies of the cub-histidine-tyrosine centre in cytochrome c oxidase
dc.contributor.author | Lee, Sang Tae | en_US |
dc.date.accessioned | 2022-03-21T16:25:47Z | |
dc.date.available | 2022-03-21T16:25:47Z | |
dc.date.issued | 2005 | en_US |
dc.description.abstract | This thesis reports the synthesis and copper coordination chemistry of covalently-linked aryl-imidazole derivatives designed as models for the crosslinked imidazole-phenol sidechains of the His-Tyr cofactor in the CcO. Three new imidazole- (HL1 - HL3) and three new indole- (HL4 - H2L6) containing tripodal ligands were synthesised. The conjugate addition of an imidazole to activated quinone derivatives was developed as a new route to organic models for the Tyr His cofactor. Two monodentate imidazole-aryl, Im-hq(OH)2 and Im-ArOH, and an imidazole-quinone, Im bq were obtained using this route. The X-ray crystal structure of Im-hq(OH)2.EtOH was determined. The route was also used to give new chelating ligands, H2L10 and HL12, containing a cross-linked imidazole-phenol surrogate for the Tyr244-His240 cofactor. Copper complexes of Im-hq(OH)2, Im-bq, Im-ArOH, H2L10-HL12, and HL1-H2L6 were prepared, and the X-ray crystal structures of [Cu(terpy)(Im-bq)][BF4]2 and five other copper complexes were determined. The physiochemical properties of the copper complexes were characterized by FT-IR, UV-Vis-NIR, EPR and (spectro)electrochemical studies. Key results include: the oxidation of Im-ArO- anion affords the semiquinone radical, Im-sq(4OH)(1O�), in a hydrous solvent. However, the oxidations of neutral Im-ArOH and [Cu(tpa)(Im-ArOH)]2+ produce the corresponding phenoxy radical species that rapidly and reversibly dimerise to give quinol cyclohexadienone, QCHD, dimers. Significantly [Cu(tpa)(Im-sq(4OH)(1O�))]2+ was EPR silent, perhaps due to antiferromagnetic coupling between the Cu(II) (S=1/2) and semiquinonyl radical (S=1/2) centres. Deprotonation of the hydroquinone in [Cu(tpa)(Im-hq(OH)2]2+ produces the hydroquinone dianion which reduces the Cu(II) centre. The semiquinone radical is coordinatively labile and dissociates from the Cu(I) centre. The biological implications of these results are mentioned. | en_US |
dc.identifier.uri | http://hdl.handle.net/1959.4/33251 | |
dc.language | English | |
dc.language.iso | EN | en_US |
dc.publisher | UNSW, Sydney | en_US |
dc.rights | CC BY-NC-ND 3.0 | en_US |
dc.rights.uri | https://creativecommons.org/licenses/by-nc-nd/3.0/au/ | en_US |
dc.subject.other | Cytochrome C oxidase | en_US |
dc.subject.other | Histidine | en_US |
dc.subject.other | Tyrosine | en_US |
dc.title | Model studies of the cub-histidine-tyrosine centre in cytochrome c oxidase | en_US |
dc.type | Thesis | en_US |
dcterms.accessRights | open access | |
dcterms.rightsHolder | Lee, Sang Tae | |
dspace.entity.type | Publication | en_US |
unsw.accessRights.uri | https://purl.org/coar/access_right/c_abf2 | |
unsw.identifier.doi | https://doi.org/10.26190/unsworks/17765 | |
unsw.relation.faculty | Science | |
unsw.relation.originalPublicationAffiliation | Lee, Sang Tae, Chemistry, Faculty of Science, UNSW | en_US |
unsw.relation.school | School of Chemistry | * |
unsw.thesis.degreetype | PhD Doctorate | en_US |
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