A polar interactions is any interaction (favorable or unfavorable) between two polar molecules. Recall that polar molecules do NOT have an overall charge but that one end of the molecule (or functional group within the molecule) is slightly negative while the other end of the molecule is equally and oppositely charged. This means that polar molecules will have some attraction for each other IF they are oriented correctly. Since every charge "carries around" its opposite counterpart within the same molecule. The interaction between polar molecules is attenuated even further (relative to the ionic interaction that we discussed in the previous page) The most remarkable difference is in how distance between polar molecules affects the magnitude.
the strength of the interaction now depends on the inverse of the CUBE (1/r3) of the distance between them. This considerably shortens the range of the interaction (relative to the ionic interaction which depended only on the inverse of the distance (1/r))
Shown here is a favorable interaction between the sidechain of GLN and that of SER.Recall the even an unfavorable interaction is a polar interaction.