Laboratories

Research

Main Scientific Achievements

• We uncovered a novel mechanism by which cells regulate metal selectivity, demonstrating that a pair of closely related metalloenzymes from cyanobacteria, with nearly identical metal selectivity, are loaded in vivo with different metals, from opposite ends of the Irving-Williams series.
• We identified the founding members of a new family of copper storage proteins, the Csps, characterising a novel component of bacterial copper homeostasis with implications for copper handling and utilisation by important environmental bacteria and medically important pathogens.
• We demonstrated a unique evolutionary adaptation in Staphylococcus aureus that enables this pathogen to survive the manganese starvation that it experiences during infection of the host through its evolution of a ‘cambialistic’ superoxide dismutase enzyme that exhibits cofactor flexibility, catalysing its reaction with either manganese or iron.

Research Description

All life on Earth depends on metals. Although present in trace quantities relative to the six organic elements that constitute biological macromolecules, the essential metals (Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Mo) play crucial roles that make them indispensable to biology. They act as charge carriers, as messengers in cell signaling, and hold together the structures of metal-requiring proteins (metalloproteins). Most importantly they directly participate in chemical reactions as essential cofactors for metal-dependent enzymes (metalloenzymes). It’s estimated that approximately one-third of all proteins in nature require metals, with an even higher proportion of enzymes predicted to require metals for catalysis.

My laboratory aims to understand the essential roles of metal ions in the structure and function of individual metalloproteins and metalloenzymes. We combine core methods in biochemistry, structural biology and biophysics to interrogate the mechanisms by which proteins utilise metals to impart structure or to facilitate catalysis, and in turn, how the protein architecture exploits and manipulates the reactivity of the metal ions. We seek to clarify the molecular mechanisms that regulate the metal specificity of metalloenzymes, i.e. their requirement to associate with one specific type of metal ion to perform their catalysis optimally, and the metal selectivity of metalloproteins, i.e. their metal binding preferences.

Furthermore, we study the mechanisms of metal homeostasis, the processes by which cells control metal availability. Due to their essential nature and their inherent potential for toxicity, all living cells possess complex, integrated cellular systems for controlling intracellular metal uptake through regulation of metal import, export, intracellular delivery, storage and sensing. Homeostasis is crucial in ensuring that each metal-requiring protein becomes associated only with its correct, target metal ion in vivo, preventing their inactivation by binding the ‘wrong’ metal ion. Homeostasis also prevents deleterious effects on the cell caused by excess concentrations of metal ions.

Methodology

Our lab uses a multidisciplinary approach to study primarily bacterial systems. Our in vitro studies leverage core methods in biochemistry, combined with structural biology and biophysics, to interrogate the structure and function of individual metalloproteins and metalloenzymes. We combine this with microbiological methods to understand the role of those metalloproteins and metalloenzymes in living cells through genetic manipulation of bacteria for phenotypic analysis, biochemical assay, and multi-omics approaches. To facilitate these studies, we collaborate with numerous world-leading laboratories.

Selected Publications

• An evolutionary path to altered cofactor specificity in a metalloenzyme. Barwinska-Sendra A, Garcia YM, Sendra KM, Baslé A, Mackenzie ES, Tarrant E, Card P, Bicep C, Un S, Kehl-Fie TE, Waldron KJ. Nature Communications, 11, 2738. 2020. https://doi.org/10.1038/s41467-020-16478-0.
• A superoxide dismutase capable of using iron or manganese promotes the resistance of Staphylococcus aureus to calprotectin and nutritional immunity. Garcia YM, Barwinska-Sendra A, Tarrant E, Skaar EP, Waldron KJ, Kehl-Fie TE. PLoS Pathogens, 13, e1006125. 2017. https://doi.org/10.1371/journal.ppat.1006125.
• A four-helix bundle stores copper for methane oxidation. Vita N, Platsaki S, Baslé A, Allen SJ, Paterson NG, Crombie AT, Murrell JC, Waldron KJ & Dennison C. Nature, 525, 140-3. 2015. https://doi.org/10.1038/nature14854.
• Metalloproteins and metal sensing. Waldron KJ, Rutherford JC, Ford D & Robinson NJ. Nature, 460, 823-830. 2009. https://doi.org/10.1038/nature08300.
• Protein-folding location can regulate manganese versus copper- or zinc-binding. Tottey S, Waldron KJ, Firbank SJ, Reale B, Bessant C, Sato K, Cheek TR, Gray J, Banfield MJ, Dennison C & Robinson NJ. Nature, 455, 1138-1142. 2008. https://doi.org/10.1038/nature07340.

Collaborations

• Thomas Kehl-Fie, School of Molecular & Cellular Biology, University of Illinois at Urbana Champaign, USA, https://mcb.illinois.edu/faculty/profile/kehlfie/.
• Sun Un, Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, Gif-sur-Yvette, France, https://frisbi.eu/centers/south-paris/epr/.
• Julie Morrissey, Department of Genetics and Genome Biology, University of Leicester, Leicester, UK, https://www2.le.ac.uk/departments/genetics/people/morrissey.
• Xingxiang Chen, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China, https://cvmen.njau.edu.cn/info/1231/1184.htm.
• Karrera Djoko, Department of Biosciences, Durham University, Durham, UK, https://www.durham.ac.uk/staff/karrera-djoko/.
• Jon Marles-Wright, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK, http://www.marles-wright-lab.org/.

Prizes and Awards

• Arturo Leone Young Investigator Award. 2018. 11th International Copper Meeting, Italy.