Carbohydrate-pi interactions: what are they worth?
Protein-carbohydrate interactions play an important role in many biologically important processes. The recognition is mediated by a number of noncovalent interactions, including an interaction between the alpha-face of the carbohydrate and the aromatic side chain of the protein. To elucidate this interaction, it has been studied in the context of a beta-hairpin in aqueous solution, in which the interaction can be investigated in the absence of other cooperative noncovalent interactions. In this beta-hairpin system, both the aromatic side chain and the carbohydrate were varied in an effort to gain greater insight into the driving force and magnitude of the carbohydrate-pi interaction. The magnitude of the interaction was found to vary from -0.5 to -0.8 kcal/mol, depending on the nature of the aromatic ring and the carbohydrate. Replacement of the aromatic ring with an aliphatic group resulted in a decrease in interaction energy to -0.1 kcal/mol, providing evidence for the contribution of CH-pi interactions to the driving force. These findings demonstrate the significance of carbohydrate-pi interactions within biological systems and also their utility as a molecular recognition element in designed systems.
Department of Chemistry, CB 3290, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Zachary R
ZR
Laughrey
Sarah E
SE
Kiehna
Alex J
AJ
Riemen
Marcey L
ML
Waters
D002236:Carbohydrate Conformation; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D055672:Static Electricity; D013816:Thermodynamics
D002241:Carbohydrates; D010455:Peptides