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In its 88-year story, the mission of our institute has been to carry out excellence research in fundamental and applied physical chemistry, contributing to the scientific training of several generations of researchers at the highest level. Our vision is to be an international reference in multidisciplinary research focused on the resolution of the present challenges of our society in the fields of health, biotechnology, new materials, and environment.

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January 2021
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webMetabolic resistance to insecticides is the biggest threat to the continued effectiveness of malaria vector control. In the frame of a transnational research program, we have demonstrated that a single amino acid change in the glutathione-s-transferase confers high levels of DDT resistance in the African mosquito Anopheles funestus.  Interestingly, this metabolic resistance marker perfectly correlates with patterns of DDT resistance across Africa. The x-ray structures of two polymorphic GSTe2 corresponding to those populations presenting an intensified resistance or sensitiveness phenotypes show that the mutation confers resistance by enlarging the GSTe2 DDT-binding cavity leading to increased DDT access and metabolism. This knowledge constitutes a valuable tool for future operational monitoring of insecticide resistance in Africa and allows us to design novel molecules with enhanced insecticide properties.

Reference:

A single mutation in the GSTe2 gene allows tracking of metabolically based insecticide resistance in a major malaria vector

Riveron JM, Yunta C, Ibrahim SS, Djouaka R, Irving H, Menze BD, Ismail HM, Hemingway J, H. Ranson, A. Albert  and C.S. Wondji
Genome Biology 2014, 15:R27 (25 February 2014)

Highlighted at:

Insecticide resistance comes of age (ffrench-Constant RH Genome Biology 2014, 15:106 (25 February 2014))

 

On Monday 17 we will have Carlos Villar, from Bruker, to give us an introduction to the use of the FTIR spectrometer Tensor-27. It will take about 3 hours, and he will bring a liquid cell and an ATR setup.

 

The Tensor-27 spectrometer is part of the biophysics lab of use for the IQFR members, located at room 324.

brukerFTIR

 

We will have a get-together to give our farewell to Isabel Cabo as manager of the Institute. It will take place at the hall in front of room 300 at 13:00-13:30. 

“How do pneumococci and other bacteria subvert the function of human proteins”

Friday 29th, 12:00

Room 300

Magnetic Properties Across Metal to Insulator Transitions

Room 300, Friday 10th January, 10:30

streptococcus pneumoniaeThe respiratory pathogen Streptococcus pneumoniae has evolved efficient mechanisms to resist oxidative stress conditions and to displace other bacteria in the nasopharynx. Here we characterize at physiological, functional and structural levels two novel surface-exposed thioredoxin-family lipoproteins, Etrx1 and Etrx2. The impact of both Etrx proteins and their redox partner methionine sulfoxide reductase SpMsrAB2 on pneumococcal pathogenesis was assessed in mouse virulence studies and phagocytosis assays. The results demonstrate that loss of function of either both Etrx proteins or SpMsrAB2 dramatically attenuated pneumococcal virulence in the acute mouse pneumonia model and that Etrx proteins compensate each other. The deficiency of Etrx proteins or SpMsrAB2 further enhanced bacterial uptake by macrophages, and accelerated pneumococcal killing by H2O2 or free methionine sulfoxides (MetSO). Moreover, the absence of both Etrx redox pathways provokes an accumulation of oxidized SpMsrAB2 in vivo. Taken together our results reveal insights into the role of two extracellular electron pathways required for reduction of SpMsrAB2 and surface-exposed MetSO. Identification of this system and its target proteins paves the way for the design of novel antimicrobials.

Reference:
Malek Saleh, Sergio G. Bartual, Mohammed R. Abdullah, Inga Jensch, Tauseef M. Asmat, Lothar Petruschka, Thomas Pribyl, Juan A. Hermoso* and Sven Hammerschmidt*
Molecular architecture of Streptococcus pneumoniae surface thioredoxin-fold lipoproteins crucial for extracellular oxidative stress resistance and maintenance of virulence
EMBO Molecular Medicine (2013) 5, 1852-1870  (doi:10.1002/emmm.201202435)

Referencia:

Malek Saleh, Sergio G. Bartual, Mohammed R. Abdullah, Inga Jensch, Tauseef M. Asmat, Lothar Petruschka, Thomas Pribyl, Juan A. Hermoso* and Sven Hammerschmidt*

Molecular architecture of Streptococcus pneumoniae surface thioredoxin-fold lipoproteins crucial for extracellular oxidative stress resistance and maintenance of virulence

EMBO Molecular Medicine (2013) 5, 1852-1870  (doi:10.1002/emmm.201202435)

We will have the traditional yearly meeting to briefly review 2013 at the main conference rooma t 13:00 and an informal lunch afterwards.

Cest-2923 figure-2

The alpha/beta hydrolase fold is one of the most versatile structures in the protein realm according to the diversity of sequences adopting such a three dimensional architecture. We found that the versatility of a canonical alpha/beta-hydrolase fold, particularly that of the carboxylesterase Cest-2923 from the lactic acid bacterium Lactobacillus plantarum WCFS1, also extends to its oligomeric behavior in solution. Thus, we discovered that Cest-2923 exhibits a pH-dependent pleomorphic behaviour in solution involving monomers, canonical dimers and tetramers. Whereas at neutral pH the system is mainly shifted to dimeric species, at acidic conditions tetrameric species predominate. Interestingly, despite that these tetramers result from the association of canonical dimers, as commonly found in many other carboxylesterases from the hormone-sensitive lipase family, they can be defined as “non canonical” since they represent a different association mode. The observed associative behaviour is consistent with different crystallographic results of Cest-2923 from structural genomics consortia. Finally, we benefit from the presence of sulphate or acetate molecules (depending on the crystal form analysed) in the close vicinity of the nucleophile Ser116, to identify interactions with the putative oxyanion hole and also to deduce the existence of hydrolytic activity within Cest-2923 crystals.

 

 

Reference:
Benavente R, Esteban-Torres M, Acebrón I, de Las Rivas B, Muñoz R, Alvarez Y, Mancheño JM. “Structure, biochemical characterization and analysis of the pleomorphism of carboxylesterase Cest-2923 from Lactobacillus plantarum WCFS1”. FEBS J. 2013 Oct 16. doi: 10.1111/febs.12569.