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The partial charge of the nitrogen atom in peptide bonds
Author(s) -
MilnerWhite E. James
Publication year - 1997
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560061125
Subject(s) - charge (physics) , partial charge , nitrogen , atom (system on chip) , chemistry , nitrogen atom , resonance (particle physics) , contradiction , peptide , peptide bond , chemical physics , atomic physics , physics , quantum mechanics , organic chemistry , philosophy , computer science , group (periodic table) , epistemology , biochemistry , embedded system
A majority of the standard texts dealing with proteins portray the peptide link as a mixture of two resonance forms, in one of which the nitrogen atom has a positive charge. As a consequence, it is often believed that the nitrogen atom has a net positive charge. This is in apparent contradiction with the partial negative charge on the nitrogen that is used in force fields for molecular modeling. However, charges on resonance forms are best regarded as formal rather than actual charges and current evidence clearly favors a net negative charge for the nitrogen atom. In the course of the discussion, new ideas about the electronic structure of amides and the peptide bond are presented.