Francesca ZITO ’s research is focused on two principal axes: structure/function relationships in the cytochrome b6f complex and overexpression of membrane proteins in a-cellular systems.
Structure/function relationships in the cytochrome b6f complex: Cytochrome b6f complexes are present in oxygen producing chloroplasts and cyanobacteria where they are facing saturating oxygen concentrations. In order to clear up the role of two mysterious cofactors, the ci heme and the chlorophyll, a site directed mutagenesis approach was chosen, changing the environment of the heme and of the chlorophyll should help to gain information on the role of both cofactors in the cytochrome b6f turn over.
Overexpression of membrane proteins in a-cellular systems: Over-expression of MPs is extremely tricky because, unlike soluble proteins, these pro¬teins, to be functional, have to be targeted and inserted into the membrane and this insertion process represents a limiting factor for protein production. One strategy to overcome this problem is to synthesize pro¬teins in a cell-free system (CFS) in the absence of a biological membrane but in the presence of either detergent micelles or liposomes. Francesca Zito is engaged in the optimisation of the coupling of CFS and new surfactactants. She could demonstrate the compatibility of the fluorinated surfactants with CFS, a fully functional mechano-sensitive channel was produced in vitro and the generality of such a class of molecule for the CFS was confirmed for other MPs.
In parallel we demonstrate that the non-ionic amphipols are suitable for proteins as BR and GPCR or multimeric complexes.
This topic is founded on several collaborations that are the real hub of this project (coll A. Polidori, Avignon; I. Mus-Veteau Nice; E. Pebay-Peyroula, Grenoble; J.L. Baneres, Montpellier; L. de la Maza, Irvine)
Laboratoire de Biologie Physico-Chimique des Protéines Membranaires UMR 7099 - IBPC
13 rue Pierre et Marie Curie F-75005 Paris, France
Mail : francesca.zito(at)ibpc.fr
Lab Web page: http://www.ibpc.fr/UMR7099/