Functional control of a 0.5 MDa TET aminopeptidase by a flexible loop revealed by MAS NMR

作者：Diego F. Gauto, P. Macek, D. Malinverni, H. Fraga, M. Paloni, Iva Sučec, Audrey Hessel, Juan P. Bustamante, A. Barducci, P. Schanda · 发表于：Nature Communications · 年份：2021 · DOI：10.1038/s41467-022-29423-0 · 被引用次数：21 · 研究领域：Medicine、Biology

Large oligomeric enzymes control a myriad of cellular processes, from protein synthesis and degradation to metabolism. The 0.5 MDa large TET2 aminopeptidase, a prototypical protease important for cellular homeostasis, degrades peptides within a ca. 60 Å wide tetrahedral chamber with four lateral openings. The mechanisms of substrate trafficking and processing remain debated. Here, we integrate magic-angle spinning (MAS) NMR, mutagenesis, co-evolution analysis and molecular dynamics simulations and reveal that a loop in the catalytic chamber is a key element for enzymatic function. The loop is able to stabilize ligands in the active site and may additionally have a direct role in activating the catalytic water molecule whereby a conserved histidine plays a key role. Our data provide a strong case for the functional importance of highly dynamic - and often overlooked - parts of an enzyme, and the potential of MAS NMR to investigate their dynamics at atomic resolution. Motion is key to enzymatic catalysis. Gauto et al. show that a flexible loop region is crucial for the function of an aminopeptidase and show that magic-angle spinning NMR provides atomic-level quantitative insights in this very large complex.