Biomaterial Database

Molecular dynamics simulation study of ion interactions with zwitterions. 2011

Qing Shao, and Yi He, and Shaoyi Jiang

Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States.

Using molecular dynamics simulations, we investigated the associations between two zwitterions (carboxybetaine and sulfobetaine) and four types of cations (Li(+), Na(+), K(+), and Cs(+)) in aqueous solutions. We studied the number and lifetime of various zwitterion-cation associations and observed that both carboxybetaine and sulfobetaine have the same order of association number and lifetime: Li(+) > Na(+) > K(+) > Cs(+). Simulation results showed that the association variation as a function of cation types for these two zwitterions is significantly different. The effect of anion type on the order was also investigated by varying the type of anions from Cl(-) to Br(-) and F(-). In order to further investigate zwitterion-cation association, we simulated the systems either with one type of zwitterion and two types of cations or with one type of cation and both carboxybetaine and sulfobetaine presented. This allowed direct competition between the solutes, and the observed association number and lifetime validated the order. Simulation results further demonstrated that, although CB associates stronger with Li(+) and Na(+) than SB, the latter is associated preferentially by K(+) and Cs(+).

UI	MeSH Term	Description	Entries
D008094	Lithium	An element in the alkali metals family. It has the atomic symbol Li, atomic number 3, and atomic weight [6.938; 6.997]. Salts of lithium are used in treating BIPOLAR DISORDER.	Lithium-7,Lithium 7
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002412	Cations	Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.	Cation
D002586	Cesium	A member of the alkali metals. It has an atomic symbol Cs, atomic number 55, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.	Caesium,Caesium-133,Cesium-133,Caesium 133,Cesium 133
D001622	Betaine	A naturally occurring compound that has been of interest for its role in osmoregulation. As a drug, betaine hydrochloride has been used as a source of hydrochloric acid in the treatment of hypochlorhydria. Betaine has also been used in the treatment of liver disorders, for hyperkalemia, for homocystinuria, and for gastrointestinal disturbances. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1341)	Lycine,Oxyneurine,Acidin-Pepsin,Betaine Hydrochloride,C.B.B.,Citrate de Bétaïne Beaufour,Citrate de Bétaïne UPSA,Cystadane,Glycine Betaine,Hepastyl,Novobetaine,Scorbo-bétaïne,Stea-16,Acidin Pepsin,AcidinPepsin,Betaine, Glycine,Hydrochloride, Betaine,Scorbo bétaïne,Scorbobétaïne,Stea 16,Stea16
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D056004	Molecular Dynamics Simulation	A computer simulation developed to study the motion of molecules over a period of time.	Molecular Dynamics Simulations,Molecular Dynamics,Dynamic, Molecular,Dynamics Simulation, Molecular,Dynamics Simulations, Molecular,Dynamics, Molecular,Molecular Dynamic,Simulation, Molecular Dynamics,Simulations, Molecular Dynamics