Conformation prediction, side chain hydrophobicity

Because of the hydrophobic character of the side chain, these amino acids are usually involved in protein or enzyme constmction but rarely in protein fimction [86-88]. The main issues in the study of such aliphatic a-amino acids are the increase of conformational possibiUties from the multiple configurations associated to torsion about single bond in the lateral chain. Two conformers of types I and II shown in Fig. 13 were ultimately detected in the supersonic jet for valine, isoleucine, and leucine, and conclusively identified through comparison of the experimental rotational and " N nuclear quadrupole coupling constants with the predicted values ab initio, as described in Sect. 3. 

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