Hyperfine-shifted 13C resonance assignments in an iron-sulfur protein with quantum chemical verification: aliphatic C-H···S 3-center-4-electron interactions.

ABSTRACT: Although the majority of noncovalent interactions associated with hydrogen and heavy atoms in proteins and other biomolecules are classical hydrogen bonds between polar N-H or O-H moieties and O atoms or aromatic π electrons, high-resolution X-ray crystallographic models deposited in the Protein Data Bank show evidence for weaker C-H···O hydrogen bonds, including ones involving sp(3)-hybridized carbon atoms. Little evidence is available in proteins for the (even) weaker C-H···S interactions described in the crystallographic literature on small molecules. Here, we report experimental evidence and theoretical verification for the existence of nine aliphatic (sp(3)-hybridized) C-H···S 3-center-4-electron interactions in the protein Clostridium pasteurianum rubredoxin. Our evidence comes from

SUBMITTER: Westler WM 

PROVIDER: S-EPMC3033705 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature