Talbot H L, Myers D B
Infect Immun. 1977 Oct;18(1):28-34. doi: 10.1128/iai.18.1.28-34.1977.
The binding of sodium [195Au]aurothiomalate (ATM) to whole cells of Mycoplasma arthritidis has been measured within the temperature range of 4 to 53 degrees C. The time course (kinetics) and the effect of varying the total concentration of free ATM in the suspension at 37 degrees C were also measured. The extent of binding at 37 degrees C leveled off after 30 min at approximately 65 nCi of [195Au]ATM per mg of membrane protein. The amount of ATM bound per cell appeared to be directly proportional to the concentration of free ATM in the range of 0.25 to 0.60 muCi of [195Au]ATM per ml. An Arrhenius plot showed two distinct regions with slopes of -0.56 degrees K/mg of protein (5 to 22 degrees C) and -2.78 degrees K/mg of protein (22 to 53 degrees C). The break in the Arrhenius plot corresponds to a temperature known to be related to a sudden change in mycoplasma membrane fluidity. Estimations of Scatchard binding constants and number of binding sites per membrane protein molecule resulted in 0.8 to 1.4 sites per molecule in the intact organisms compared to 1.4 to 1.8 sites in membrane fragments. The latter were purified by repeated washings in phosphate-buffered saline after alkaline lysis of the cells. It is suggested that ATM reacts with available protein sulfhydryl groups in the mycoplasmal membrane.
已在4至53摄氏度的温度范围内测量了硫代苹果酸金钠（[195Au]ATM）与关节炎支原体全细胞的结合情况。还测量了37摄氏度下结合的时间进程（动力学）以及悬浮液中游离ATM总浓度变化的影响。在37摄氏度时，结合程度在30分钟后趋于稳定，每毫克膜蛋白约结合65纳居里的[195Au]ATM。每个细胞结合的ATM量似乎与每毫升0.25至0.60微居里[195Au]ATM范围内的游离ATM浓度成正比。阿累尼乌斯图显示出两个不同区域，斜率分别为-0.56摄氏度/毫克蛋白（5至22摄氏度）和-2.78摄氏度/毫克蛋白（22至53摄氏度）。阿累尼乌斯图中的断点对应于一个已知与支原体膜流动性突然变化有关的温度。对斯卡查德结合常数和每个膜蛋白分子结合位点数量的估计结果表明，完整生物体中每个分子有0.8至1.4个位点，而膜片段中有1.4至1.8个位点。后者是在细胞经碱性裂解后用磷酸盐缓冲盐水反复洗涤纯化得到的。提示ATM与支原体膜中可用的蛋白质巯基发生反应。
