Belgrade : The Bioinformatics Research Group, University of Belgrade - Faculty of Mathematics
Abstract
CH/O interactions represent weak hydrogen bonds that stabilize protein structures
where they contribute up to 25% among the total number of detected
hydrogen bonds. Previously, we showed that CH/O interactions do not show
strong preference for linear contacts and that the energy of CH/O interactions
of aromatic CH donors depends on the type of atom or group in ortho-position to
the interacting CH group [1, 2]. In this work, CH/O interactions of aromatic CH
donors within proteins have been studied by analyzing the data in the Protein
Data Bank (PDB) and by quantum chemical calculations of electrostatic potentials.
The CH/O interactions were studied between three aromatic amino acids;
phenylalanine, tyrosine and tryptophan, with several acceptors.
The analysis of the distribution of the CHO angle in the crystal structures from
the PDB indicates no preference for linear CH/O interactions between aromatic
donors and acceptors in protein structures. Although there is no tendency for
linear CH/O interactions, there is no significant number of bifurcated CH/O
interactions. The analyses also indicate an influence of simultaneous classical
hydrogen bonds. The influence is particularly observed in case of tyrosine. The
hydroxyl group of aromatic ring of tyrosine plays an important role by forming
a simultaneous classical hydrogen bond along with CH/O interaction in orthoposition
to the OH substituent. These investigations could help in future CH/O
interactions studies in proteins or other proteic systems.Belgrade, Serbia, June 20-24, 201