A5027997186- Enzyme Structure and Function
- Protein Structure and Dynamics
- Mycobacterium research and diagnosis
- Tuberculosis Research and Epidemiology
- Biochemical and Molecular Research
- RNA and protein synthesis mechanisms
- Bacterial Genetics and Biotechnology
- Soil Carbon and Nitrogen Dynamics
- Microbial Metabolic Engineering and Bioproduction
- Photosynthetic Processes and Mechanisms
- Enzyme Production and Characterization
- Antibiotic Resistance in Bacteria
- Streptococcal Infections and Treatments
- Glycosylation and Glycoproteins Research
- thermodynamics and calorimetric analyses
- Antimicrobial Resistance in Staphylococcus
- Microbial Natural Products and Biosynthesis
- Amino Acid Enzymes and Metabolism
- Bacteriophages and microbial interactions
- Microbial Community Ecology and Physiology
- Genomics and Phylogenetic Studies
- Soil and Unsaturated Flow
- Biofuel production and bioconversion
- Enzyme Catalysis and Immobilization
- Toxin Mechanisms and Immunotoxins
University of Waikato
2015-2024
Victoria University of Wellington
2023
University of Auckland
2007-2022
Maurice Wilkins Centre
2008-2022
AgResearch
2002-2014
University of Oslo
2007-2009
Princeton University
2009
Sunny BioDiscovery (United States)
2004
Massey University
2002
Medical Research Council
1994
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...
Future anticipated warming could reduce the terrestrial carbon sink by ~50% mid-century.
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...
Many enzymes display non-Arrhenius behavior with curved Arrhenius plots in the absence of denaturation. There has been significant debate about origin this and recently role activation heat capacity (ΔCP⧧) widely discussed. If enzyme-catalyzed reactions occur appreciable negative values ΔCP⧧ (arising from narrowing conformational space along reaction coordinate), then are a consequence. To investigate these phenomena detail, we have collected high precision temperature-rate data over wide...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTpKA Values of Carboxyl Groups in the Native and Denatured States Barnase: The pKA State Are on Average 0.4 Units Lower Than Those Model CompoundsMikael Oliveberg, Vickery L. Arcus, Alan R. FershtCite this: Biochemistry 1995, 34, 29, 9424–9433Publication Date (Print):July 25, 1995Publication History Published online1 May 2002Published inissue 25 July...
Mycobacterium tuberculosis has evolved a number of strategies to survive within the hostile environment host phagocytes. Reactive nitrogen and oxygen intermediates (RNI ROI) are among most effective antimycobacterial molecules generated by during infection. Lsr2 is M. protein with histone-like features, including ability regulate variety transcriptional responses in mycobacteria. Here we demonstrate that protects mycobacteria against ROI vitro macrophage Furthermore, using macrophages...
The chromosome of Mycobacterium tuberculosis (Mtb) encodes forty seven toxin-antitoxin modules belonging to the VapBC family. role these in physiology Mtb and function(s) served by their expansion are unknown. We investigated ten vapBC from single M. smegmatis. Of vapCs assessed, only Rv0549c, Rv0595c, Rv2549c Rv2829c were toxic when expressed a tetracycline-regulated promoter same genes displayed toxicity conditionally Mtb. Toxicity smegmatis correlated with level protein expressed,...
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...
The largest family of toxin-antitoxin (TA) modules are encoded by the vapBC operons, but their roles in bacterial physiology remain enigmatic. Microarray analysis Mycobacterium smegmatis overexpressing VapC/VapBC revealed a high percentage downregulated genes with annotated carbon transport and metabolism, suggesting that VapC was targeting specific metabolic mRNA transcripts. To validate this hypothesis, purified used to identify RNA cleavage site vitro. had RNase activity sequence...
Abstract Heat capacity changes are emerging as essential for explaining the temperature dependence of enzyme-catalysed reaction rates. This has important implications enzyme kinetics, thermoadaptation and evolution, but physical basis these heat is unknown. Here we show by a combination experiment simulation, two quite distinct enzymes (dimeric ketosteroid isomerase monomeric alpha-glucosidase), that activation change catalysed can be predicted through atomistic molecular dynamics...
Quantifying the rate of thermal adaptation soil microbial respiration is essential in determining potential for carbon cycle feedbacks under a warming climate. Uncertainty surrounding this topic stems part from persistent methodological issues and difficulties isolating interacting effects changes community responses availability. Here, we constructed series temperature response curves (given unlimited substrate) using soils sampled around New Zealand, including natural geothermal gradient,...