A5087498002- Enzyme Production and Characterization
- Glycosylation and Glycoproteins Research
- Antimicrobial Resistance in Staphylococcus
- Carbohydrate Chemistry and Synthesis
- Antibiotic Resistance in Bacteria
- Polysaccharides and Plant Cell Walls
- Genomics and Phylogenetic Studies
- Protein Structure and Dynamics
- Pneumonia and Respiratory Infections
- Seaweed-derived Bioactive Compounds
- Bacterial biofilms and quorum sensing
- Enzyme Structure and Function
- Biofuel production and bioconversion
- Lysosomal Storage Disorders Research
- Clostridium difficile and Clostridium perfringens research
- Bacterial Genetics and Biotechnology
- Microbial Metabolism and Applications
- Enzyme Catalysis and Immobilization
- Polymer crystallization and properties
- Chemical Synthesis and Analysis
- Microbial Metabolic Engineering and Bioproduction
- thermodynamics and calorimetric analyses
- Bacterial Identification and Susceptibility Testing
- Photosynthetic Processes and Mechanisms
- Proteins in Food Systems
University of St Andrews
2024-2025
University of Victoria
2015-2024
University of Waikato
2011-2016
University of Leeds
2005-2011
Leeds General Infirmary
2011
European Synchrotron Radiation Facility
2003
University of Bristol
2003
Bristol Robotics Laboratory
1996
One of the critical variables that determine rate any reaction is temperature. For biological systems, effects temperature are convoluted with myriad (and often opposing) contributions from enzyme catalysis, protein stability, and temperature-dependent regulation, for example. We have coined phrase "macromolecular theory (MMRT)" to describe dependence enzyme-catalyzed rates independent stability or regulatory processes. Central MMRT observation reactions occur significant values ΔCp(‡) in...
The increase in enzymatic rates with temperature up to an optimum (Topt) is widely attributed classical Arrhenius behavior, the decrease above Topt ascribed protein denaturation and/or aggregation. This account persists despite many investigators noting that insufficient explain decline Topt. Here we show it change heat capacity associated enzyme catalysis (ΔC‡p) and its effect on dependence of ΔG‡ determines activity. Through mutagenesis, demonstrate correlated ΔC‡p changes are sufficient...
Our current understanding of the temperature response biological processes in soil is based on Arrhenius equation. This predicts an exponential increase rate as rises, whereas laboratory and field, there always a clearly identifiable optimum for all microbial processes. In laboratory, this has been explained by denaturation enzymes at higher temperatures, availability substrates water often cited critical factors. Recently, we have shown that optima growth occur absence consequence unusual...
The proposed lethal action of daptomycin on Staphylococcusaureus results from the loss K+ and membrane depolarization. However, whether these events alone cause cell death has been questioned. We sought to determine other consequences daptomycin-mediated damage may contribute death. Previously established assays were used evaluate damaging activity at a single time-point 10 min. More detailed time-course experiments also performed kinetics depolarization leakage K+, Mg2+ ATP. inhibition...
Thermophily is thought to be a primitive trait, characteristic of early forms life on Earth, that has been gradually lost over evolutionary time. The genus Bacillus provides an ideal model for studying the evolution thermophily as it ancient taxon and its contemporary species inhabit range thermal environments. thermostability reconstructed ancestral proteins used proxy adaptation. reconstruction "enzymes" added advantages demonstrable activity, which acts internal control accurate...
Significance Pectin and alginate are polysaccharides found in the cell walls of plants brown algae, respectively. These largely consist chains uronates, which can be metabolized by bacteria through a pathway enzymatic steps to key metabolite 2-keto-3-deoxygluconate (KDG). Understanding metabolism these sugars is important because pectin degradation used many plant-pathogenic during infection, both represent abundant sources carbohydrate for production biofuels. Here we demonstrate that KdgF,...
The carbohydrate-rich coating of human tissues and cells provide a first point contact for colonizing invading bacteria. Commensurate with N-glycosylation being an abundant form protein glycosylation that has critical functional roles in the host, some host-adapted bacteria possess machinery to process N-linked glycans. pathogen Streptococcus pneumoniae depolymerizes complex N-glycans enzymes sequentially trim N-glycan down Man3GlcNAc2 core prior release glycan from by...
Abstract Pseudoalteromonas is a globally distributed marine-associated genus that can be found in broad range of aquatic environments, including association with macroalgal surfaces where they may take advantage these rich sources polysaccharides. The metabolic systems confer the ability to metabolize this abundant form photosynthetically fixed carbon, however, are not yet fully understood. Through genomics, transcriptomics, microbiology, and specific structure-function studies pathway...
XF-73 is a novel porphyrin antibacterial agent previously reported to inhibit range of gram-positive bacterial species, including Staphylococcus aureus. Its mode action unknown. Using S. aureus as model organism we sought examine the basis its activity.The effects on growth and survival SH1000 were investigated by viable count culture absorbance techniques. Inhibition macromolecular synthesis disruption membrane integrity after exposure examined radiolabelling experiments, BacLight...
Carrageenans are a complex group of polysaccharides derived from the cell walls red macroalgae. They an abundant, yet recalcitrant nutrient source for most marine heterotrophic bacteria. Some member species Pseudoalteromonas genus effective at metabolizing carrageenan. However, enzymatic pathway λ-carrageenan, one sulfated naturally occurring polysaccharides, remains unknown. Using detailed structural analysis by X-ray crystallography we reveal sophisticated and cyclic cascade deployed...
The resurrection of ancestral proteins provides direct insight into how natural selection has shaped found in nature. By tracing substitutions along a gene phylogeny, can be reconstructed silico and subsequently synthesized vitro. This elegant strategy reveals the complex mechanisms responsible for evolution protein functions structures. However, to date, all studies have used simplistic approaches sequence reconstruction (ASR), including assumption that single alignment alone is sufficient...
Pectin is a complex uronic acid-containing polysaccharide typically found in plant cell walls, though forms of pectin are also marine diatoms and seagrasses. Genetic loci that target have recently been identified two phyla bacteria. These appear to encode saccharification pathway distinct from the canonical associated with phytopathogenic terrestrial However, very few components metabolism experimentally validated. Here, we biochemically reconstructed Pseudoalteromonas sp. vitro show it...
Therapeutic options in Clostridium difficile infection (CDI) are limited. We examined linezolid activity vitro and potential therapeutic efficacy using a gut model of CDI. MICs were determined by agar incorporation for 118 diverse C. faecal isolates, including epidemic strains with reduced susceptibility to metronidazole. CDI was established two experiments (ribotypes 027 106) dosed achieve human concentrations. Linezolid demonstrated good against 98% the isolates. Two isolates (PCR...
Antibiotic tolerance is an underappreciated antibiotic escape strategy that associated with recurrent and relapsing infections, as well acting a precursor to resistance. Tolerance describes the ability of bacterial population survive transient exposure otherwise lethal concentration without exhibiting elevated MIC. It detected in time-kill assays lower rate killing than susceptible strain can be quantified by metric minimum duration for (MDK). The molecular mechanisms behind are varied, but...
The stringent response (SR) is a universal stress that acts as global regulator of bacterial physiology and virulence, contributor to antibiotic tolerance resistance. In most bacteria, the SR controlled by bifunctional enzyme, Rel, which both synthesizes hydrolyzes alarmone (p)ppGpp via two distinct catalytic domains. balance between these antagonistic activities fine-tuned needs cell and, in "relaxed" state, hydrolase activity Rel dominates. We have previously shown single amino acid...
Ultralong alkanes crystallize into lamellae with a thickness that is an integer fraction of the extended chain length. On heating, they unfold or thicken to approach equilibrium, form. Using high-resolution in-situ wide-angle X-ray scattering, carried out at European Synchrotron Radiation Facility (ESRF), Grenoble, it has been shown this thickening accompanied by contraction lattice, accompanying each event between folded crystal thickness. Prior thickening, there increase in disorder, as...