通过铊-205核磁共振研究二价阳离子与掺入脂质环境中的短杆菌肽A结合的热力学参数。
Thermodynamic parameters for the binding of divalent cations to gramicidin A incorporated into a lipid environment by Tl-205 nuclear magnetic resonance.
作者信息
Hinton J F, Fernandez J Q, Shungu D C, Millett F S
机构信息
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville 72701.
出版信息
Biophys J. 1989 Feb;55(2):327-30. doi: 10.1016/S0006-3495(89)82808-5.
Thermodynamic parameters, enthalpy and entropy, for the binding of the divalent cations, Mg+2, Ca+2, Sr+2, Ba+2, and Cd+2, to gramicidin A, incorporated into lysophosphatidylcholine, have been determined using a combination of Tl-205 nuclear magnetic resonance spectroscopy and competition binding. The binding process is thermodynamically driven by the enthalpy and not the entropy. The enthalpy values are related to the process involving the transfer of cations from an aqueous environment to an amide environment. A comparison is made between the thermodynamic parameters for the binding of monovalent and divalent cations to gramicidin A to illustrate the channel blocking ability of the divalent cations with respect to monovalent cation transport.
利用铊-205核磁共振光谱法和竞争结合法相结合，测定了二价阳离子镁离子（Mg²⁺）、钙离子（Ca²⁺）、锶离子（Sr²⁺）、钡离子（Ba²⁺）和镉离子（Cd²⁺）与掺入溶血磷脂酰胆碱中的短杆菌肽A结合的热力学参数，即焓和熵。结合过程在热力学上是由焓而非熵驱动的。焓值与阳离子从水环境转移到酰胺环境的过程有关。对单价和二价阳离子与短杆菌肽A结合的热力学参数进行了比较，以说明二价阳离子对单价阳离子运输的通道阻断能力。
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