• Login
• Admin

Andrea, Bombana (2024) A Minimal Peptide Scaffold for [4Fe-4S]-Cluster Interrogation and Catalysis. PhD thesis, University of Nottingham.

Preview

PDF (Corrections) (Thesis - as examined) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader Available under Licence Creative Commons Attribution. Download (14MB) | Preview

Abstract

The S-adenosyl-L-methionine (SAM) dependant superfamily of enzymes is capable of initiating a variety of biologically essential radical reactions. Likewise, bacterial-type ferredoxins mediate electron transfer to facilitate a broad range of biological redox processes. Both families of enzymes host a cubic [4Fe-4S]2+/+ motif that initiates and mediates the reactivity of these proteins.

The synthesis of short peptide maquettes that mimic the conserved cysteine-rich motif responsible for coordinating the [4Fe-4S] cluster represents an exciting and easy-to synthesise tool with which to explore the utility of these systems. In Chapters 2 and 3 of this thesis we describe the preparation of a series of cluster maquettes to gather information regarding the influence of the local electronic and steric environment on the formation and redox potential of the cluster, as well as exploring the stability of the clusters to aerobic conditions. Despite being routinely formed under strict anaerobic conditions, the use of photoactivated NADH is herein described for the successful reduction of oxidised [4Fe-4S] cluster when reconstituted in presence of atmospheric oxygen. Different peptides mimicking both the radical SAM and bacterial-type ferredoxins families are investigated in this thesis with the aim of producing an engineered maquette. In Chapter 4 we demonstrate the integration of synthetic, bacterial ferredoxin-type maquette into a H2-powered electron transport chain to showcase the potential utility of these systems within synthetic biology.

Site-selective methods for peptide and protein modification allow for the late-stage installation of various moieties into peptides and enable protein engineering via bioconjugation. In Chapter 5 of this thesis, we describe a visible-light-mediated desulfurative C(sp3)-C(sp2) bond forming method that enables the site-selective installation of aromatic analogues into small peptides.

Disulphide bonds are well known for playing a key role in defining and stabilising proteins structures. More recently, data has revealed that disulphide bonds are crucially involved in oxygen sensing by interacting with oxidising agents. In Chapter 6 of this thesis, we investigate the effect that different amino acids in close proximity to a cysteine residue involved in the disulphide bond can have on the reduction of the disulphide in small peptide models. Computational simulations were conducted to integrate the experimental data.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Nicholas, Mitchell Anna, Croft
Keywords:	peptides, cysteine, iron-sulphur clusters
Subjects:	Q Science > QD Chemistry > QD146 Inorganic chemistry Q Science > QP Physiology > QP501 Animal biochemistry
Faculties/Schools:	UK Campuses > Faculty of Science > School of Chemistry
Item ID:	77493
Depositing User:	Bombana, Andrea
Date Deposited:	24 Jul 2024 04:41
Last Modified:	24 Jul 2024 04:41
URI:	https://eprints.nottingham.ac.uk/id/eprint/77493

Actions (Archive Staff Only)

Edit View