Reciprocal carbonyl-carbonyl interactions in small molecules and proteins

Abdur Rahim, Pinaki Saha, Kunal Kumar Jha, Nagamani Sukumar, Bani Kanta Sarma

Research output: Contribution to journalArticlepeer-review

Abstract

Carbonyl-carbonyl n→π* interactions where a lone pair (n) of the oxygen atom of a carbonyl group is delocalized over the π* orbital of a nearby carbonyl group have attracted a lot of attention in recent years due to their ability to affect the 3D structure of small molecules, polyesters, peptides, and proteins. In this paper, we report the discovery of a "reciprocal" carbonyl-carbonyl interaction with substantial back and forth n→π* and π→π* electron delocalization between neighboring carbonyl groups. We have carried out experimental studies, analyses of crystallographic databases and theoretical calculations to show the presence of this interaction in both small molecules and proteins. In proteins, these interactions are primarily found in polyproline II (PPII) helices. As PPII are the most abundant secondary structures in unfolded proteins, we propose that these local interactions may have implications in protein folding.Carbonyl-carbonyl π* non covalent interactions affect the structure and stability of small molecules and proteins. Here, the authors carry out experimental studies, analyses of crystallographic databases and theoretical calculations to describe an additional type of carbonyl-carbonyl interaction.

Original languageEnglish
Pages (from-to)78
JournalNature Communications
Volume8
Issue number1
DOIs
Publication statusPublished - 19 Jul 2017

Keywords

  • Crystallization
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Models, Chemical
  • Models, Molecular
  • Protein Conformation
  • Protein Structure, Secondary
  • Proteins/chemical synthesis
  • Software

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