One of the smallest motors found in nature are in the membrane of bacteria. These flagellar nanomotors turn at a very high rate propelling their host through a liquid media. The structure and operation of this motor based on many interlocking proteins has not been elucidated. We propose to mass produce and purify the constitutive proteins of this motor by using molecular recombinant techniques and print theses proteins on prepared biomimetic surfaces to observe and study their self assembly and mechanism of interaction. The proteins production and purification will be done by our american partner on the project, Dr John Sternick from Mansfield University, PA. The goal is to understand how the proteins interact and how they are instrumental to the building and functioning of the E Coli nanomotor. The "artificial" building of this biological motor, block after block, on a solid surface using soft lithography is a technological challenge that couples state of the art techniques of protein production, surface chemistry, nanolithography, self assembly and dynamic imaging. The technology and conceptual understanding derived from this research will enhance greatly the ultimate goal of building a functional nanomotor in vitro. The project assembles three different disciplines: Biology, Nanotechnology and Biophysics.

     As the first step of the project we propose a model which describes how the motor works. This model will play the role of bases of the project, because we will assemble the protein in order to reproduce the organization supported by the model. This model was elaborated by Dr John Sternick and Jerome Chalmeau in Mansfield. When we start to work on the flagellum nanomotor, one thing appears as a fundamental factor for us: the spatial agency of all the proteins. The motor needs a very specific spatial arrangement of all his blocks for working well and propels the bacteria through the media. Without it, the proteins implied on the rotation can not interact with each others and the bacteria can not move. We will compare the motor we will elaborate based on the model we supported and compare it with the natural assembly of the motor. The experimental part of the project will consist of assembling differents part of the nanomotor which are known to be implied in the rotation. We will start with the FliM FliN proteins. We will print theses proteins in a circular pattern with a dimension closed of the natural assembly and we will observe with a AFM in liquid media with high resolution the result. These experiments would confirm or decline our vision of the natural assembly of the motor. This project could also demonstrate it would be possible to recreate artificially on a surface some auto assembly structures found in the nature,a prelude to an artificial assembly of biological nanomotor.  

Our model:
     The rotary motor found at the base of the flagella in E Coli can turn rapidly in either Clockwise (CW) or counterclockwise (CCW) direction by using a proton gradient across the internal membrane of the bacteria as a torque generating force; In early rotationnal models, the stator, comprised of MotA and MotB, is hypothesized to change its configuration when subjected by the flow of protons. The change in configuration transmits a rotational force to FliG component of the rotor base, causing the rapide rotation of the flagella in one direction. The reversal of rotor direction is problematic in this model. In addition there is no membrane bound molecualr control mechanism for proton flow and no consideration given to the role of CheY-P. In other models in the litterature, it has been suggested that reversal of rotor rotation could be due to either conformational switching of charged groups on the rotor or reversible proton channels in the stator. To answer these problemes we propose a simple mechanism of flagellar rotation which encompasses MotA and MotB ability to interact reversibly with FliG. This new model complies with the molecular and structural data analysis and observation found in the litterature.
     In essence, for each "unit" of rotation, there is one MotB and twos MotA ( MotA1 and MotA2):

                                       one unit of rotation of the stator

     The MotAs are geared into each other so that as one rotates in a clockwise direction the other rotates in the opposite direction, i.e. counterclockwise. These two MotAs, 1 and 2, turn continuously due to the incessant flow of protons through the motB which acts as a proton conduit. If MotA1 is in contact with the FliG, the motor turns clockwise and if the MotA2 is in contact with the FliG, the motor turns counterclockwise. The mechanism that controls which MotA is in contact with the FliG is an elastic protein ring made up of FliMs and FliNS at the base of the flagellar nanomotor which can be in a relaxed or tensed form depending on its interaction with the CheY-P. When relaxed, MotA1 contacts FliG and when tensed MotA2 replaces it.
This project was born 2 years ago in Mansfield University due to a collaboration between Jerome Chalmeau and Dr John Sternick from the Biology department and it came true when Jerome Chalmeau met Christophe Vieu (responsable of the NANO-group of the LAAS) after he came back to France. Today there is 5 top different laboratories (Biology departement from Mansfield University,PA, USA; NANO-group in the LAAS, LBB in INSA, IPBS and CBS in Montpellier, who work together on that project and a website dedicaced exclusively to the project will be opened soon.
A video is now available and describes the model and you can email me for watching it to :  jchalmea@laas.fr