98
A. Bagaria and S. Ramakumar
Z-isomer
E-isomer
Fig. 3 Isomers of dehydrophenlalanine residue Z-isomer (Phe z ) and E-isomer (Phe E )
2.1.2 Geometric Features of Phe
Phe is an achiral molecule and its interesting conformational features enable the
design of structural elements of proteins. The backbone conformation constraining
property to the Phe is imparted due to the double between C
α and C
β atoms. The
double bond is the consequence of dehydrogenation of saturated amino acid phenylalanine at C
α and C
β atoms, which involve the conversion of the sp
3 hybridization
states of C
α and C
β atoms into sp
2 states (Fig. 4). This results in certain changes in
geometrical features of Phe. There is an extended conjugation of the Phe ring
electrons with sp
2 hybridized C
α and C
β atoms. This renders the Phe residue a
±60º or
180º
Phe
Phe
Double Bond
0º
Δ
Fig. 4 The coded and the non-coded amino acid Phenylalanine (Phe) and α, βdehydrophenylalanine (Phe)
A. Bagaria and S. Ramakumar
Z-isomer
E-isomer
Fig. 3 Isomers of dehydrophenlalanine residue Z-isomer (Phe z ) and E-isomer (Phe E )
2.1.2 Geometric Features of Phe
Phe is an achiral molecule and its interesting conformational features enable the
design of structural elements of proteins. The backbone conformation constraining
property to the Phe is imparted due to the double between C
α and C
β atoms. The
double bond is the consequence of dehydrogenation of saturated amino acid phenylalanine at C
α and C
β atoms, which involve the conversion of the sp
3 hybridization
states of C
α and C
β atoms into sp
2 states (Fig. 4). This results in certain changes in
geometrical features of Phe. There is an extended conjugation of the Phe ring
electrons with sp
2 hybridized C
α and C
β atoms. This renders the Phe residue a
±60º or
180º
Phe
Phe
Double Bond
0º
Δ
Fig. 4 The coded and the non-coded amino acid Phenylalanine (Phe) and α, βdehydrophenylalanine (Phe)