Which statement is incorrect about the peptide bond?

Options

A. `C-N` bond length in proteins is longer than usual bond length of `C-N` bond
B. Spectroscopic analysis shows planer structure of `-underset(O)underset(||)(C)-NH-"group"`
C. `C-N` bond length in proteins in smaller than usual bond length of `C-N` bond
D. None of these

Answer

A

Explanation

Peptide bonds `(-NH - CO -)` tend to assume a geometry such that six atoms of the amide linkage are coplanar. The carbon-nitrogen bond of the amide linkage is unusually short, indicating that resonance contirbutions of the type shown below are important
Consequently, the carbon-nitrogen bond has considerable double-bond character `(~40%)` and rotation of groups about this bond are severely hindered.