[SCAN] Ricardo Louro

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Title: Studies of multiheme cytochromes c from anaerobic bacteria that use metals to sustain their bioenergetic metabolism.

Speaker: Ricardo Louro

Affiliation: Ricardo O. Louro Lab - Inorganic Biochemistry and NMR

Abstract:

Multiheme cytochromes are recognized key players in numerous anaerobic metabolic processes, some of which can be traced to very ancient activities such as photoferrotrophism and dissimilatory metal or sulfate reduction. Some of these metabolic capabilities are nowadays being co-opted for the development of microbial electrochemical technologies that rely on the role of multiheme cytochromes for connecting the microbial metabolism to solid conducting surfaces.

The structure of cytochromes with up to 16 hemes per polypeptide chain has been reported and decaheme cytochromes appear to be very common. The detailed functional characterization of such complex proteins is compounded by the fact that most spectroscopic techniques do not provide sufficient discrimination of the individual hemes.

NMR spectroscopy is a very powerful tool to study these proteins since it can provide the necessary discrimination of the individual hemes even while the protein is poised at different degrees of oxidation. This allows for the detailed characterization of their microscopic redox properties and for characterizing protein-protein or protein-ligand interactions that are usually transient and weak.

The elucidation of the organization of electron transfer networks of metal metabolizing bacteria and the characterization of the molecular mechanisms performed by multiheme cytochromes using NMR spectroscopy will be presented. together with insights into novel strategies for extending the capabilities of NMR spectroscopy to more complex cytochromes.