NanoMech - Controling the nanomechanic os viral and bacterial infections: from molecules to cells

Bacteria and viruses infect organisms using proteins as attaching elements to the surface of the host. HIV-1 uses its envelope glycoprotein gp120 to attach to CD4 in the surface of T cell. Similarly, the bacterium E. coli uses an array of proteins called pilus for establishing mechanical anchoring to tissues. These proteins withstand mechanical forces that go from few to hundreds of picoNewtons. The effect of these forces in the structure and chemistry of the proteins is not fully understood but it may have implications in the infection process. In this proposal, we will continue our investigations on the role of mechanical forces in the structure and chemistry of the microbial attachment proteins as well as the infection process. We will use an array of techniques to study the nanomechanics of viral and bacterial infections progressively from single molecules to cells. We aim to establish new knowledge of the molecular aspects that drive the mechanical interaction of microbes with their targets. First, we will use atomic force spectroscopy to explore the effect of mechanical forces in microbial attachment proteins, human CD4 and E. coli pilus. This technique allows monitoring chemical reactions under force such as the reduction of disulfide bonds or the binding of peptides, small molecules and antibodies, processes which are known to be implicated in microbial infections and that may have a mechanical origin. We have already published initial work that demonstrates how force can modify the structure and chemistry of the two most external domains of human CD4.

In the same vein, using force spectroscopy we have demonstrated the chemistry of DsbA, the enzyme responsible of disulfide bridge formation in the bacterial pilus. Both discoveries were framed under the aims of our previous project and demonstrate the validity of our initial hypothesis. Second, we will incorporate to our research new confocal imaging techniques and magnetic tweezers to design molecular force sensors based on fluorescence for establishing correlations between cellular and molecular mechanics. We have already designed the force sensor using green fluorescence protein and the initial results are quite promising. Finally, we will use bioinformatics to search for molecules that alter the mechanical properties of these anchoring proteins and that can potentially be used to prevent infections. We have also advanced on this objective and found compounds in the ZINC chemical library that alter the mechanics of CD4 and that are currently being tested as potential HIV-1 entry inhibitors. In summary, the present proposal is a continuation of our previous work in which we advanced in every objective demonstrating the validity of our initial hypothesis and encouraging us to pursuit our research. Viral and bacterial infections are widely studied but there is not much information in the context of mechanical interactions. We believe that we are providing unprecedented results that will soon show results for our continious fight against microbial infections as one of the main challenges of our society.

This project is funded by BIO2016-77390-R / MCIN/ AEI /10.13039/501100011033/ FEDER UE, Una manera de hacer Europa