Specification of binding modes between a transmembrane peptide mimic of ATP6V0C and polytopic E5 of human papillomavirus-16.

Interaction of E5 of papillomavirus-16 based on its three transmembrane domains (TMDs) with a peptide mimicking the fourth TMD (TMD-A) of the 16 kDa c subunit of the human vacuolar H-ATPase, ATP6V0C, and one of its mutant is investigated. Docking reveals binding of the peptide between the second and third TMD of E5. A series of hydrophobic residues are responsible for the contact. Estimated weak binding energies based on potential of mean force calculations reveal marginal differences of the estimated binding energies between wild type (WT) and mutant peptide. Also differences in estimated binding energies of dimers of the individual TMDs of E5 with the WT peptide are marginal. Correlation of rotational data derived from coarse-grained molecular dynamics simulations of the peptides and the protein as well as from the principal component analysis reveal that the binding of TMD-A with TMD3 is enthalpy driven and binding with TMD2 is guided by entropic conditions.