Comunicazione
A theoretical framework for understanding proteins.
vSkrbic T., Banavar J.R., Giacometti A., Hoang T.X., Maritan A.
Proteins, molecular machines of life, are complex with myriad degrees of freedom. Linus Pauling used quantum chemistry to predict the structures of protein modular building blocks, helices and strands assembled into sheets. Pauling and others adopted a backbone-based view, focusing on the importance of the backbone atoms, the avoidance of steric clashes, and hydrogen bonds. An alternative side chain centered view pointed out the additional vital importance of the role of the solvent, distinct hydrophilic/hydrophobic character of amino acid chains, and the need to sequester the hydrophobic core from the solvent. I will present the results of ongoing work to reconcile these two approaches. Protein building blocks are space-filling structures. Using mathematical and physics ideas, we work out an interaction energy which promotes these structures, as well as a solvent-mediated attraction that correctly assembles the building blocks, while respecting their individual symmetries. Our approach deftly avoids the use of quantum chemistry, is in accord with experimental data, underscoring the consilience in the fit of chemistry and biology to the dictates of mathematics and physics.