Stability and Dynamics of Domain‐Swapped Bovine‐Seminal Ribonuclease

The proteins of the ribonuclease‐A (RNase‐A) family are monomeric, with the exception of bovine‐seminal ribonuclease (BS‐RNase). BS‐RNase is formed by swapping the N‐terminal helices across the two monomeric units. A molecular‐dynamics (MD) study has been performed on the protein for a simulation time of 5.5 ns to understand the factors responsible for the stability of the dimer. Essential dynamics analysis and motional correlation of the protein atoms yielded the picture of a stabilising, yet flexible, interface. We have investigated the role of intermolecular H‐bonding, protein/water interaction, and protein/water networks in stabilising the dimer. The networks of interchain H‐bonds involving side‐chain/side‐chain or side‐chain/main‐chain (ScHB) interactions between the two chains have also been studied. The ability of protein atoms in retaining particular H 2 O molecules was investigated as a function of the accessible surface area ( ASA ), depth , and hydration parameters, as well as their participation in protein/water networks.