Frumkin Institute of Physical chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia.
Toxins (Basel). 2022 Sep 26;14(10):669. doi: 10.3390/toxins14100669.
Secreted phospholipases A2 (sPLA2s) are peripheral membrane enzymes that hydrolyze phospholipids in the position. The action of sPLA2 is associated with the work of two active sites. One, the interface binding site (IBS), is needed to bind the enzyme to the membrane surface. The other one, the catalytic site, is needed to hydrolyze the substrate. The interplay between sites, how the substrate protrudes to, and how the hydrolysis products release from, the catalytic site remains in the focus of investigations. Here, we report that bee venom PLA2 has two additional interface binding modes and enzyme activity through constant switching between three different orientations (modes of binding), only one of which is responsible for substrate uptake from the bilayer. The finding was obtained independently using atomic force microscopy and molecular dynamics. Switching between modes has biological significance: modes are steps of the enzyme moving along the membrane, product release in biological milieu, and enzyme desorption from the bilayer surface.
分泌型磷脂酶 A2(sPLA2)是一种位于细胞膜表面的外周膜酶,可水解磷脂分子的 sn-2 位酯键。sPLA2 的作用与两个活性位点的协同相关。其中,界面结合位点(IBS)负责将酶结合到膜表面,而催化位点则负责水解底物。目前,研究的重点在于探究这两个位点之间的相互作用、底物如何突出到催化位点以及水解产物如何从催化位点释放。在此,我们报告称,蜂毒 PLA2 通过在三种不同构象(结合模式)之间不断切换,具有两种额外的界面结合模式和酶活性,其中只有一种模式负责从双层膜中摄取底物。该发现是通过原子力显微镜和分子动力学独立获得的。模式之间的切换具有生物学意义:模式是酶沿膜移动、产物在生物环境中释放以及酶从双层膜表面解吸的步骤。