Phenylalanine is a naturally occurring amino acid, (a) What is the energy of int
ID: 68068 • Letter: P
Question
Phenylalanine is a naturally occurring amino acid, (a) What is the energy of interaction between its phenyl group and the electric dipole moment of a neighboring peptide group? Take the distance between the groups as 4.0 A and treat the phenyl group as a benzene molecule. The dipole moment of the peptide group is about 2.7 D and the polarizability of benzene is about 1.04 Times 10^-29 m^3. If the distance was 40 A, what would the interaction strength be? Now consider the dispersion interaction between the phenyl groups of two phenylalanine residues. Estimate the potential energy of interaction between two such rings (treated as benzene molecules) separated by (a) 4.0 A and by (b) 40 A. For the ionization energy, use 5.0 eV.Explanation / Answer
Take the distance between the groups as 4.0 nm and treat the phenyl group as a benzene molecule. The dipole moment of the peptide group is µ = 2.7 D and the polarizability volume of benzene is = 1.04 × 1029 m3.
2.2 mT, g = 1.992.