热通过融化轴向自身抑制塞来激活 AAA+ HslUV 蛋白酶。

Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Cell Rep. 2021 Jan 19;34(3):108639. doi: 10.1016/j.celrep.2020.108639.

At low temperatures, protein degradation by the AAA+ HslUV protease is very slow. New crystal structures reveal that residues in the intermediate domain of the HslU unfoldase can plug its axial channel, blocking productive substrate binding and subsequent unfolding, translocation, and degradation by the HslV peptidase. Biochemical experiments with wild-type and mutant enzymes support a model in which heat-induced melting of this autoinhibitory plug activates HslUV proteolysis.

在低温下，AAA+ HslUV 蛋白酶对蛋白质的降解非常缓慢。新的晶体结构揭示，HslU 解旋酶中间结构域中的残基可以堵塞其轴向通道，阻止有效底物结合以及随后的解旋、易位和 HslV 肽酶的降解。对野生型和突变酶的生化实验支持这样一种模型，即该自动抑制塞的热诱导融化激活 HslUV 蛋白水解。