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Smilja Todorovic Lab

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We are interested in fundamental questions and biotechnological applications of metalloenzymes. Employing advanced vibrational spectroscopy and spectroelectrochemistry as a main tool, we study enzymes involved in catalysis, detoxification, signaling, respiration and DNA repair and probe molecular processes at interfaces using tailored nanostructured metal-enzyme hybrids.

 

Smilja Todorovic
Principal Investigator
PhD in 2000, Belgrade University, Serbia /Mayo Clinic Graduate school, USA

Phone (+351) 214469717 | Extension 1717
smilja@itqb.unl.pt

 

Research Interests

We use physical tools, spectroscopy and spectroelectrochemistry, to investigate biophysico-chemical properties of metalloproteins, aiming at understanding how different proteins fine-tune the reactivity of their metal cofactors and how such metal centers help to tailor the dynamics and stability of protein molecules. Metal centers constitute active sites of over one third of all enzymes; we use resonance Raman (RR) spectroscopy to sensitively and selectively probe structural features of such metal centers, including heme, non-hemic iron, Fe-S, Co and Cu cofactors.

            By wiring redox enzymes to biocompatible conductive supports, we design metalloenzyme-electrode constructs to study molecular processes at interfaces. Interfacial reactions are ubiquitous in biology and also constitute the basis for the functioning of enzyme-supported biocatalytic and biosensoric devices. These enzyme-electrode hybrids allow us to take advantage of the high specificity of enzymatic reactions that are driven by the controllable electron source (nanostructured metallic electrode) which, at the same time, gives origin to surface enhancement of RR signal. In this manner we simultaneously monitor bioelectrocatalysis and structural properties of immobilized metalloenzymes (e.g.  micro- and DyP peroxidases, cyt P450 and nitrite reductases), employing Surface Enhanced RR (SERR) spectroelectrochemistry. We also use SERR to study mechanistic properties of immobilized membrane proteins. Here, we probe electron transfer properties of metalloproteins attached to metal electrodes and embedded in lipid bilayers, which mimic basic features of physiological membranes, such as restricted mobility and influence of strong interfacial electric fields. Moreover, we tailor electrode coatings to mimic enzyme´s substrate or co-immobilize physiological redox partners and probe the respective interactions along catalytic / redox reactions, employing constructs like DNA : DNA glycosylases,  cyt c552 : cd1 NiR, etc.

 

Group Members

  • Celia Silveira, post doc fellow

 

Selected Publications

 

  1. Todorovic, S. 2016 ‘Surface-Enhanced Raman Scattering of Biological Materials’ in Encyclopedia of Analytical Chemistry, eds R. A. Meyers, John Wiley & Sons: Chichester DOI: 10.1002 / 9780470027318.a9574.

  2. Moe, E., Hildebrandt, P., Sezer, M., Todorovic, S. 2015 ´Surface enhanced vibrational spectroscopic evidence for an alternative DNA-independent redox activation of Endonuclease III´ Chem. Comm. 51, 3255-3257

  3. Todorovic, S., Pereira M., Bandeiras, T., Teixeira, M., Hildebrandt, P., and Murgida, D. 2005 ´Midpoint potentials of hemes a and a3 in the quinol oxidase from Acidianus ambivalens are inverted´ J. Am. Chem. Soc. 127, 13561-13566

Laboratory's Website

For further information visit the laboratory's website

 

Espectroscopia de Raman de Metaloproteínas (PT)

Estamos interessados em questões fundamentais e aplicações biotecnológicas de metaloenzimas. Utilizando espectroscopia vibracional avançada e espectroeletroquímica como ferramentas principais, estudamos enzimas envolvidas em catálise, destoxificação, sinalização, respiração e reparação de ADN. A espectroscopia de ressonância Raman (RR) permite caracterizar, com elevada sensibilidade e selectividade, propriedades estruturais e mecanísticas de enzimas com centros ativos de ferro hémico e não hémico, ferro-enxofre, cobalto e cobre.

Ligando enzimas redox a suportes condutores biocompatíveis, construímos híbridos metaloenzima-elétrodo que possibilitam o estudo de processos moleculares interfaciais e representam também a base do funcionamento de biossensores e biocatalisadores enzimáticos. Utilizando técnicas como a RR aumentada por superfície (SERRS), avaliamos em simultâneo propriedades estruturais destas enzimas immobilizadas e a sua actividade bioelectrocatalítica. Para poder estudar as interações inter-moleculares, temos desenvolvido superfícies que mimetizam os substratos enzimáticos ou que permitem a co-imobilização de parceiros fisiológicos das enzimas.

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