Isabelle Broutin

Website: https://www.citcom.cnrs.fr/
ORCID: 0000-0001-9862-1232
Twitter: @BroutinI

Structural study of membrane proteins

Our team, specialized in the structural study of membrane proteins, focuses its research on the public health problem of antibiotic resistance responsible for the dramatic increase of multi-resistant bacteria all over the word. Among the different ways used by bacteria to resist to antibiotics, the active efflux through tripartite efflux pumps is one of the most important. Our main target is Pseudomonas aeruginosa (PA), a nosocomial opportunistic pathogen that contributes to the decline of respiratory function in cystic fibrosis (CF) patients. PA possesses mainly four efflux pumps proven to be involved in the efflux of antibiotics, with some specificities concerning the family of antibiotics taken in charge. Different strategies can be considered to develop molecules blocking the function of these pumps such as the perturbation of the energy system, the maintaining of the porin in its closed conformation, or the prevention of the assembly. We are conducting this research by complementary approaches linking structural biology (X-ray crystallography, SAXS, Cryo-EM) with in cellulo functional analysis. We recently managed to describe the assembly of the constitutive efflux pump MexA-MexB-OprM by cryo-electronic microscopy in close collaboration with the team of Dr Lambert in Bordeaux University (Glavier, Nat Comm, 2020), making possible a drug design approach.

In parallel, we have initiated different projects:

– the study of the PA efflux pump expression regulators, in close collaboration with the team of Dr C. Llanes (University of Besançon)
– we model the possible effect of single-mutations identified in clinical PA strains isolated from the spits of cystic fibrosis patients in collaboration with the team of Pr P. Plesiat (CHU Besançon, “Centre National de Référence de la Résistance aux Antibiotiques”)
– we evaluate the role of post-translational modifications (PTM) on specific proteins involved in regulation mechanisms, with a particular focus on lysine acetylation, in collaboration with the team of Dr J. Hardouin (University of Rouen).

Structural biology, membrane protein production and purification

Our team is specialized in structural biology, membrane protein production and purification, protein/protein or protein/ligand interaction characterization by different biophysical approaches
We are equipped with a mosquito robot for protein crystallization, a fluorimeter and an ITC
We have a regular access to the synchrotrons localized in France, and to the Pasteur cryo-EM microscope

Top 5 publications

1- Molecular Determinants for OMF Selectivity in Tripartite RND Multidrug Efflux Systems. Boyer E, Dessolin J, Lustig M, Decossas M, Phan G, Cece Q, Durand G, Dubois V, Sansen J, Taveau JC, Broutin I, Daury L, Lambert O. Antibiotics (Basel). 2022;11(2):126. doi: 10.3390/antibiotics11020126.

2- MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa. Ma M, Lustig M, Salem M, Mengin-Lecreulx D, Phan G, Broutin I. Int J Mol Sci. 2021;22(10):5328. doi: 10.3390/ijms22105328.

3- Antibiotic export by MexB multidrug efflux transporter is allosterically controlled by a MexA-OprM chaperone-like complex. Glavier M, Puvanendran D, Salvador D, Decossas M, Phan G, Garnier C, Frezza E, Cece Q, Schoehn G, Picard M, Taveau JC, Daury L, Broutin I*, Lambert O*. Nat Commun. 2020;11(1):4948. doi: 10.1038/s41467-020-18770-5.

4- Functional Mechanism of the Efflux Pumps Transcription Regulators From Pseudomonas aeruginosa Based on 3D Structures. Housseini B Issa K, Phan G, Broutin I. Front Mol Biosci. 2018;5:57. doi: 10.3389/fmolb.2018.00057. eCollection 2018.

5- Xenon for tunnelling analysis of the efflux pump component OprN. Ntsogo Enguéné YV, Phan G, Garnier C, Ducruix A, Prangé T, Broutin I. PLoS One. 2017;12(9):e0184045. doi: 10.1371/journal.pone.0184045. eCollection 2017.

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