Unusual dynamic properties of water near the ice-binding plane of hyperactive antifreeze protein

Abstract

The dynamical properties of solvation water of hyperactive antifreeze protein from Choristoneura fumiferana (CfAFP) are analyzed and discussed in context of its antifreeze activity. The protein comprises of three well-defined planes and one of them binds to the surface of ice. The dynamical properties of solvation water around each of these planes were analyzed separately; the results are compared with the dynamical properties of solvation water of ice around its two crystallographic planes: basal and prism. Three main conclusions are inferred from our investigations. The first one is that the solvation shell of CfAFP does not seem to be particularly far-ranged, at least not beyond what is usually observed for proteins that do not interact with ice. Therefore, it does not appear to us that the antifreeze activity is enhanced by a long-ranged retardation of water mobility. Also the correlation between the collective mobility of water and the collective mobility of protein atoms highly resembles the one measured for the protein that does not interact with ice. Our second conclusion is that the dynamical properties of solvation water of CfAFP are non-uniform. The dynamics of solvation water of ice-binding plane is, in some respects, different from the dynamics of solvation water of the two remaining planes. The feature that distinguishes the dynamics of solvation water of the three planes is the activation energy of diffusion process. The third conclusion is that-from the three analyzed solvation shells of CfAFP-the dynamical properties of solvation water of the ice-binding plane resemble the most the properties of solvation water of ice; note, however, that these properties still clearly differ from the dynamic properties of solvation water of ice.

Crowders and Cosolvents—Major Contributors to the Cellular Milieu and Efficient Means to Counteract Environmental Stresses

“…As an amphiphilic molecule, the hydration picture of TMAO is more complex and still largely elusive. In most cases studied so far, simulations and experiments reported on the formation of strong hydrogen bonds in the hydration shell of TMAO, in terms of shorter atomic distances, increased hydrogen‐bond energy, and retarded dynamics . However, the molecular origin of the retardation is still under debate.…”

Water-mediated influence of a crowded environment on internal vibrations of a protein molecule

“…The results can be found in Table 1 and they agree with the previously published data. 49,51 As we could have expected, the mean mobility of water molecules diminishes with the increasing number of neighbors. The presence of the additional protein molecule may cause deeper changes in the solvation water properties -deeper than a single protein is able to induce.…”

“…The correlation of motion is most visible for the frequencies lower than about 2 THz and diminishes for the frequencies higher than 5 THz. As we discussed in the paper, 49 the high values for the near-zero frequencies may originate from the concerted diffusion motion of the investigated molecules. The influence of this factor can be estimated, following the concept of Lin et al 54 We have to stress, however, that this estimation is very rough.…”

“…We used the method described in our previous paper. 26,49 We investigated the cross-correlation function of the vectors of collective velocity of atoms located at the surfaces of the two neighboring AFP molecules. The details of the method are as follows.…”

“…Thus, the value of the above integral reflects the dynamic properties of water within the selected solvation layer. A relatively short cut-off time may lead to a slight overestimation of the diffusion coefficients, but as we checked and discussed before, 49 it should not cause a problem with the interpretation of the results.…”