Characterisation of three cofactor-containing proteins from the oral bacterium Fusobacterium nucleatum
department or school: Science, Irving K. Barber Faculty of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Mothersole, Robert Geoffrey
issued: 2020-07-28T18:28:44Z
issued: 2020
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Fusobacterium nucleatum, a Gram-negative oral bacterium, is linked to periodontal disease, colorectal cancer and adverse pregnancy outcomes. The research herein uncovers the kinetic, structural and mechanistic properties of three F. nucleatum proteins that are potential therapeutic targets. Chapter 2 focuses on the characterisation of flavodoxin (FnFld), an FMN-containing electron transfer protein. FnFld was shown to have the highest recorded reduction potentials amongst characterised long-chain flavodoxins. Fluorescence binding studies revealed that the elevated potentials are due to preferred binding of the FMN hydroquinone anion over the oxidised FMN quinone. The structural rationale for the electropositive reduction potentials was provided through the x-ray crystal structure of FnFld. Chapter 3 investigates the thermodynamic and biophysical effects of four naturally occurring substitutions present in FnFld. A glycine to lysine substitution in a highly conserved phosphate-binding loop does not elicit a dramatic effect on FMN binding or the redox properties of the flavin cofactor, but it does contribute to a positively charged binding cleft that may serve as a redox partner recognition site. Three other residues, Y56, N89 and F93 were shown to modulate the electropositive reduction potentials. Chapter 4 investigates lanthionine synthase (LS), which belongs to the fold II family of PLP-dependent enzymes. Although LS is catalytically promiscuous like other family members, it shows catalytic preference toward the condensation of two molecules of L-cysteine to produce lanthionine and HâS. Inspection of the LS crystal structure revealed a novel loop region containing S234 that forms electrostatic interactions with lanthionine. The catalytic importance of this residue was confirmed through mutagenesis. Chapter 5 focuses on the characterisation of a bifunctional ornithine decarboxylase/arginase (ODA). Sequence alignment revealed that ODA contains two naturally occurring …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75294
note: Characterisation of Three Cofactor-containing Proteins from the Oral Bacterium Fusobacterium nucleatum by Robert Geoffrey Mothersole M.Chem., The University of York, 2016 A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY In THE COLLEGE OF GRADUATE STUDIES (Biochemistry and Molecular Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) July 2020 © Robert Geoffrey Mothersole ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Characterisation of Three Cofactor-containing Proteins from the Oral Bacterium Fusobacterium nucleatum submitted by Robert Geoffrey Mothersole in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biochemistry and Molecular Biology Examining Committee: Dr. Kirsten Wolthers (Irving K. Barber Faculty of Science) Supervisor Dr. Kevin Smith (Irving K. Barber Faculty of Science) Supervisory Committee Member Dr. Isaac Li (Irving K. Barber Faculty of Science) Supervisory Committee Member Dr. Filip Van Petegem (Faculty of Medicine) University Examiner Dr. Todd Holyoak (University of Waterloo) External Examiner iii Abstract Fusobacterium nucleatum, a Gram-negative oral bacterium, is linked to periodontal disease, colorectal cancer and adverse pregnancy outcomes. The research herein uncovers the kinetic, structural and mechanistic properties of three F. nucleatum proteins that are potential therapeutic targets. Chapter 2 focuses on the characterisation of flavodoxin (FnFld), an FMN-containing electron transfer protein. FnFld was shown to have the highest recorded reduction potentials amongst characterised long-chain flavodoxins. Fluorescence binding studies revealed that the elevated potentials are due to preferred binding of the FMN hydroquinone anion over the oxidised FMN quinone. The structural rationale for the electropositive reduction potentials was…
has type: Thesis/Dissertation
date issued: 2020-09
is shown at: 10.14288/1.0392574
language: eng
degree discipline: Biochemistry and Molecular Biology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75294