Dales S L, Anthony C
Biochemistry Department, University of Southampton, U.K.
Biochem J. 1995 Nov 15;312 ( Pt 1)(Pt 1):261-5. doi: 10.1042/bj3120261.
A fluorescence method is described for direct measurement of the interaction between methanol dehydrogenase (MDH) and its electron acceptor cytochrome cL. This has permitted a distinction to be made between factors affecting electron transfer and those affecting the initial binding or docking process. It was confirmed that the initial interaction is electrostatic, but previous conclusions with respect to the mechanism of EDTA inhibition have been modified. It is proposed that the initial 'docking' of MDH and cytochrome cL is by way of ionic interactions between lysyl residues on its surface and carboxylate groups on the surface of cytochrome cL. This interaction is not inhibited by EDTA, which we suggest acts by binding to nearby lysyl residues, thus preventing movement of the 'docked' cytochrome to its optimal position for electron transfer, which probably involves interaction with the hydrophobic funnel in the surface of MDH.
本文描述了一种用于直接测量甲醇脱氢酶(MDH)与其电子受体细胞色素cL之间相互作用的荧光方法。这使得能够区分影响电子转移的因素和影响初始结合或对接过程的因素。已证实初始相互作用是静电作用,但关于EDTA抑制机制的先前结论已有所修正。有人提出,MDH和细胞色素cL的初始“对接”是通过其表面的赖氨酰残基与细胞色素cL表面的羧基之间的离子相互作用实现的。这种相互作用不受EDTA抑制,我们认为EDTA的作用是通过与附近的赖氨酰残基结合,从而阻止“对接”的细胞色素移动到其进行电子转移的最佳位置,这可能涉及与MDH表面疏水通道的相互作用。