Effects of hydrostatic pressure on the conformational equilibrium of tryptophan synthase from Salmonella typhimurium.
Effects of hydrostatic pressure on the conformational equilibrium of tryptophan synthase from Salmonella typhimurium.
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DOI：
10.1111/j.1749-6632.2009.05201.x
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发表时间：
2010-02
影响因子：
5.2
通讯作者：
Goody RS
中科院分区：
文献类型：
--
作者：
Phillips RS;Miles EW;McPhie P;Marchal S;Lange R;Holtermann G;Goody RS
影响色氨酸合成酶α-和β-亚基之间变构通讯的参数很多，包括一价阳离子、pH、温度、配体、有机溶剂和静水压力。通过吡哆醛-5‘-磷酸-L-丝氨酸络合物在423 nm处的吸光度或在495 nm处的荧光可以监测从封闭到开放的构象变化。压力微扰被用来量化单价阳离子、配体和突变对色氨酸合成酶构象平衡的影响。还研究了Na+、NH4+、Na+和苯并咪唑存在时的P-跳跃动力学。Lnk对P的曲线是非线性的，需要一个可压缩性(β‡o)项才能获得良好的拟合。β‡o对苯并咪唑的Na+酶呈阳性反应，对NH_4~+和Na~+呈阴性反应。这些结果表明，溶剂化作用对色氨酸合成酶构象变化的动力学有很大的贡献。升压和降压引起的P-跳跃的松弛动力学也不同，说明酶的构象是微态的集合。
A wide range of parameters influence allosteric communications between the α- and β-subunits of the Trp synthase α2β2 multienzyme complex with L-Ser, including monovalent cations, pH, temperature, ligands, organic solvents, and hydrostatic pressure. The conformational change from closed to open can be monitored either by absorbance at 423 nm or fluorescence at 495 nm from the pyridoxal-5′-phosphate-L-Ser complex. Pressure perturbation was used to quantify the effects of monovalent cations, ligands, and mutations on the conformational equilibrium of Trp synthase. P-jump kinetics in the presence of Na+, NH4+, and Na+ together with benzimidazole were also examined. The plots of lnk versus P are nonlinear and require a compressibility (β‡o) term to obtain a good fit. β‡o is positive for the Na+ enzyme but negative for NH4+ and Na+ with benzimidazole. These results suggest that there is a large contribution of solvation to the kinetics of the conformational change of Trp synthase. The relaxation kinetics are also different if the P-jumps are made by increasing or decreasing pressure, suggesting that the enzyme conformations are ensembles of microstates.
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影响因子：
2.9
作者：
Ngo, Huu;Kimmich, Novelle;Dunn, Michael F.
通讯作者：
Dunn, Michael F.
影响因子：
2.9
作者：
Weber-Ban, E;Hur, O;Dunn, MF
通讯作者：
Dunn, MF
影响因子：
2.9
作者：
Peracchi, A;Bettati, S;Dunn, MF
通讯作者：
Dunn, MF
影响因子：
4.8
作者：
RUVINOV, SB;AHMED, SA;MILES, EW
通讯作者：
MILES, EW
影响因子：
2.9
作者：
Fan, YX;McPhie, P;Miles, EW
通讯作者：
Miles, EW