Cell Physiology & NMR

 Group Leader 

Overview

Our research group started in 1986, working on a topic that, at the time, was very challenging: NMR methods to study metabolism of living cells in a non-invasive way. It was this practice of examining whole cells, instead of breaking them, that led us to the two research lines that are active today:

• Low-molecular organic solutes of microorganisms adapted to hot environments and their role in thermoprotection of cellular components;
• From physiology to Metabolic Engineering of industrial bacteria.

Hyper/thermophiles isolated from seawater sources accumulate ionic organic solutes (thermolytes) not only in response to an increase in salinity, but also in response to heat stress. These solutes are different from those used by mesophilic microorganisms for osmoadaptation. Our team characterised a number of thermolytes and demonstrated their superior efficacy on the stabilization of different biomaterials such as proteins.

Therefore, there is link between solute accumulation by (hyper)thermophiles and structural protection against heat damage. We continue our effort to screen for novel thermolytes and to answer the following questions:

• What novel pathways and enzymes are used in the synthesis of thermolytes?
• What is the total molecular and regulatory network, from sensing the stress to synthesising the solute?
• What are the molecular mechanisms underlying protein protection by thermolytes in vitro and in living cells?

We believe that the answers will lead to the design of useful tailor-made stabilizers and to new knowledge on the physiology supporting Life at high temperature.
In a second research line, we use in vivo NMR coupled with ¹³C-labelling to measure on line the dynamics of intracellular metabolites to provide useful guidelines for metabolic engineering strategies. Moreover we take advantage of NMR methodologies to characterise the metabolite profile in different microbial samples and tissues (metabolomics).

Target organisms for Metabolic Engineering: Lactococcus lactis for the production of polyols or to improve acid resistance and Corynebacterium glutamicum for the production of reagents for the chemical industry from renewable resources.

Selected publications

1. MANNOSYLGLYCERATE STABILIZES STAPHYLOCOCCAL NUCLEASE WITH RESTRICTION OF SLOW β-SHEET MOTIONS T. M. Pais, P. Lamosa, M. Matzapetakis, D. L. Turner & H. Santos. Protein Science, 21, 1126-1137 (2012). 
2. EVOLUTION OF THE BIOSYNTHESIS OF DI-MYO-INOSITOL PHOSPHATE, A MARKER OF ADAPTATION TO HOT MARINE ENVIRONMENTS L. G. Gonçalves, N. Borges, F. Serra, P. L. Fernandes, H. Dopazo & H. Santos Environmental Microbiology, 14, 691-701 (2012).
3. HIGH YIELDS OF 2,3 BUTANEDIOL AND MANNITOL IN Lactococcus lactis THROUGH ENGINEERING NAD+ COFACTOR RECYCLING P. Gaspar, A. R. Neves, M. J. Gasson, C. A. Shearman & H. Santos Applied and Environmental Microbiology, 77, 6826-6835 (2011).