Probing alkali metal-pi interactions with the side chain residue of tryptophan.
Feeble forces play a significant role in the organization of proteins. These include hydrogen bonding, hydrophobic interactions, salt bridge formation, and steric interactions. The alkali metal cation-pi interaction is a force of potentially profound importance but its consideration in biology has been limited by the lack of experimental evidence. Our previous studies of cation-pi interactions with Na(+) and K(+) involved the side arms of tryptophan (indole), tyrosine (phenol), and phenylalanine (benzene) as the arene donors. The receptor system possesses limiting steric constraints. In this report, we show that direct interactions between alkali metals and arenes occur at or within the van der Waals contact distance.
Hu
Jiaxin
J
Program in Bioorganic Chemistry, Division of Bioorganic Chemistry, Department of Molecular Biology and Pharmacology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
Barbour
Leonard J
LJ
Gokel
George W
GW
D001554:Benzene / Q000737:chemistry; D018360:Crystallography, X-Ray; D007211:Indoles / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D019800:Phenol / Q000737:chemistry; D011188:Potassium / Q000737:chemistry; D011485:Protein Binding; D012964:Sodium / Q000737:chemistry
D007211:Indoles; D008670:Metals; D019800:Phenol; C030374:indole; D012964:Sodium; D001554:Benzene; D011188:Potassium