Raman Spectroscopy of Metalloproteins
Spectroscopy studies the interaction between electromagnetic radiation and matter and has contributed considerably to our understanding of the properties of complex biological molecules.
Head of Laboratory
Smilja Todorovic | Research InterestsGroup MembersSelected PublicationsEspectroscopia de Raman de Metaloproteínas (PT) |
Phone (+351) 214469717 |
Research Interests
Spectroscopy studies the interaction between electromagnetic radiation and matter and has contributed considerably to our understanding of the properties of complex biological molecules. Raman spectroscopy is a vibrational spectroscopic technique that can provide chemical identification and structural characterization of a molecule.
Our research is focused on the biophysico-chemical aspects of the functioning of various metalloproteins. In particular, we are interested in understanding how different proteins fine-tune the reactivity of their metal cofactors and additionally, how the metal centres help to define the functional features, dynamics and stability of protein molecules. We use resonance Raman spectroscopy, in both stationary and time resolved modes, on a wide variety of structurally and functionally different proteins, sometimes with specifically designed point mutations, in order to access the details of the interplay between the protein matrix and the metal.
Resonance Raman spectroscopy of the heme, blue copper, non-hemic iron and iron-sulfur proteins that we study, can reveal highly specific and sensitive information on discrete metal site(s) within a protein. It is also capable of providing information on: the thermodynamic parameters that control electron transfer in redox proteins, the ligation pattern of the metal center, or short-lived intermediates of the catalytic cycle of an enzyme. In time-resolved mode, resonance Raman spectroscopy allows us to investigate protein dynamics and structure simultaneously over a broad time scale, from nanoseconds to hours.
We are also interested in comprehending the parameters that control the redox properties and thus functional features of bacterial respiratory chain complexes (II, III and IV). Surface enhanced resonance Raman (SERR) spectroscopy is a particularly powerful tool for studying membrane proteins as it allows the application of direct electrochemistry on the proteins immobilized on metal electrodes. Moreover, electrodes coated with biocompatible monolayers can mimic some basic features of biological interfaces and act as electron sources for driving the catalytic cycle of the enzyme, while SERR spectroscopy can provide simultaneous insight into the active site of the adsorbed species.
Group Members
- Zélia Gouveia, PhD student
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Gabriel Martins, BI fellow
Selected Publications
- Todorovic, S., Pereira M., Bandeiras, T., Teixeira, M., Hildebrandt, P., and Murgida, D. H. (2005) `Midpoint potentials of Hemes a and a3 in the Quinol Oxidase from Acidianus ambivalens are Inverted` J. Am. Chem. Soc. 127 13561-13566
- Todorovic, S., Jung, C., Hildebrandt, P., and Murgida, D. H. (2006) `Conformational Transitions and Redox Potential Shifts of Cytochrome P450 Induced by Immobilization` J. Biol. Inorg. Chem. 11 119-127
Todorovic, S. Veríssimo, A., Pereira, M., Teixeira, M., Hildebrandt, P., Zebger, I., Wisitruangsakul, N., Murgida, D. (2008) ´SERR-spectroelectrochemical study of a cbb3 oxygen reductase in a biomimetic construct´ J. Phys. Chem. B, 112 16952-16959
Laboratory's Website
For further information visit the laboratory's website
Espectroscopia de Raman de Metaloproteínas (PT)
A espectroscopia vibracional de Raman fornece identificação química e informação estrutural de uma molécula com grande especificidade. A ressonância de Raman (RR) de metaloproteínas (com ferro hémico ou não hémico, centro de cobre, etc.) permite: determinar parâmetros termodinâmicos de transferência electrónica, detecção de intermediários catalíticos e usando substituição isotópica, identificar sem ambiguidades ligandos de centros activos.
O ITQB possui uma instalação experimental, única a nível nacional para técnicas de RR especializadas para amostras biológicas. O laboratório esta equipado para a realização de RR com resolução temporal (TR-RR) de modo a estudar simultaneamente a reactividade e a estrutura de cromóforos num largo domínio temporal, desde nanosegundos até horas. A RR aumentada de superfície (SERR), acoplada com métodos electroquímicos, fornece informação sobre processos de transferência electrónica de proteínas imobilizadas em eléctrodos metálicos. O SERR permite estudar proteínas membranares em condições quase fisiológicas, por reconstituição da camada bilipídica, em plena actividade catalítica.
