Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands.
Faculty of Biology, Center for Medical Biotechnology, University Duisburg-Essen, 45117 Essen, Germany.
Structure. 2014 Feb 4;22(2):281-90. doi: 10.1016/j.str.2013.11.010. Epub 2013 Dec 26.
The protease-chaperone DegP undergoes secondary through quaternary structural changes, regulating function and preventing indiscriminate proteolysis. Several structures of DegP oligomers have been observed, including the resting state 6-mer and the 12-mer and 24-mer active states. However, the precise events of the transition between the resting and active states still need to be elucidated. We used native mass spectrometry to demonstrate that binding of multiple substrate-mimicking peptide ligands to the DegP resting state occurs prior to the transition to an active conformation. This transition occurred at a 6-mer occupancy of 40% for each peptide ligand. We observed ligand-specific 9-mer formation with a maximum load of 9 peptides, whereas other substrates led to 12-mers accommodating 24 peptides. Based on these data, we present a model for the initial steps of substrate-induced transitions from the resting to active states of DegP.
蛋白酶伴侣 DegP 经历二级到四级结构的变化，调节功能并防止无差别蛋白水解。已经观察到 DegP 寡聚物的几种结构，包括静止状态的 6 聚体和活性状态的 12 聚体和 24 聚体。然而，静止状态和活性状态之间的转变的确切事件仍需阐明。我们使用天然质谱法证明，在过渡到活性构象之前，多个底物模拟肽配体结合到 DegP 静止状态。这种转变发生在每个肽配体的 6 聚体占有率为 40%时。我们观察到配体特异性的 9 聚体形成，最大负载为 9 个肽，而其他底物则导致容纳 24 个肽的 12 聚体。基于这些数据，我们提出了 DegP 从静止状态到活性状态的底物诱导转变的初始步骤模型。
