The seminar will take place, the 5th of May 2017, at 11 am, in the IECB amphitheatre, 2 rue Robert Escarpit Pessac
Dr. Marisela VELEZ
Institute of Catalysis and Petrochemistry CSIC
FtsZ is a cytoskeletal protein that participates in the formation, on the inner side of the cytoplasmic bacterial membrane, of the “septal ring”, a protein complex responsible for cell division . We have used supported lipid bilayers and controlled orientation of FtsZ monomers in vitro to study their GTP-dependent self-assembling on surfaces with atomic force microscopy in solution, providing single molecule information of the dynamic structure of filaments and their aggregates [2-4]. A theoretical description of individual filaments that incorporates information from molecular dynamic simulations has identified that filament curvature, monomer twist, surface attachment and lateral interactions between monomers are enough to describe, using Monte Carlo simulations, some of the structures that we observe experimentally.
The implication of this work is that monomer flexibility and surface attachment, additionally to filament curvature, could be important in determining the polymorphism and dynamic behavior of filament aggregates. Furthermore, we suggest a new mechanism for force generation in which the orientation and type of monomer attachment to the surface could play an important role in modulating the force exerted by filament aggregates on the bacterial membrane during cell division . Ongoing work is directed towards testing the hypothesis that monomer attachment, flexibility and conformation are associated with the shape, rigidity and dynamics of the filaments and that this is relevant for creating tensions on the membrane.
Mingorance, J.; Rivas, G.,Vélez; M.,Gómez-Puertas, P.; Vicente, M. “Strong FtsZ is with the force: mechanisms to constrict bacteria” Trends in Microbiology 18, 348-356, (2010)
Mateos-Gil , P.; Paez ,A.; Hörger, I, Rivas, G.; Vicente,M.; Tarazona,P. and Vélez, M. “Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ” PNAS 109 8133‐8138. (2012)
González de Prado Salas, P., Encinar,M., Vélez,M. and Tarazona,P. “ FtsZ protein on bilayer membranes: effects of specific lateral bonds “ Soft Matter 9, 6072 (2013)
Encinar, M. ; Kralicek, A.; Martos, A.; Krupka, M.; Alonso, A.; Cid, Sa.; Rico, A.; Jiménez, M.; Vélez, M.“ Polymorphism of FtsZ filaments on lipid surfaces: role of monomer orientation" Langmuir 29, 9436 – 9446 (2013)
González de Prado Salas,P., Hörger,I., Martín-García,F.,J Mendieta,J.; Alvaro,A., Encinar,M., Gómez-Puertas,P., Vélez, M., and Tarazona,P. “Torsion and curvature of FtsZ" Soft Matter 10; 1977- 1986 (2014)
BACHELOR IN SCIENCE (B.S.): Biology (biochemistry) Autonomus Universtity of Madrid . June 1982
DOCTOR OF PHILOSOPHY (Ph.D): Biophysics. University of Michigan (USA) August 1989
Instituto de Catálisis y Petroleoquímica (Catalysis and Oil-chemistry Institute) C.S.I.C.
POSTAL ADDRESS: C/ Marie Curie, 2 ; Cantoblanco ; Madrid E-28049
(SPAIN) TEL: +34 91 585 4800; FAX:+34 91 585 4760
The main research interest of my group is to understand biological processes on surfaces using in vitro reconstituted systems. We address questions regarding the structure and function of macromolecular aggregates formed on lipid surfaces, particularly those relevant for bacterial cell division, using biophysical techniques as AFM, QCM, fluorescence microscopy. We combine the single molecule description of the structure and dynamic behavior of the polymers of bacterial protein FtsZ on different surfaces with theoretical analysis to understand at the molecular level the force generating mechanism of this self-assembling protein.
We also collaborate closely with the bioelectrocatalysis group to nanostructure and characterize gold electrodes
with lipidic membranes to incorporate active membrane redox proteins.