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DOI	10.1073/pnas.2025022118
	Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR
	Toyama Y.; Harkness R.W.; Lee T.Y.T.; Maynes J.T.; Kay L.E.
发表日期	2021
ISSN	00278424
卷号	118 期号:11
英文摘要	Human High temperature requirement A2 (HtrA2) is a mitochondrial protease chaperone that plays an important role in cellular proteostasis and in regulating cell-signaling events, with aberrant HtrA2 function leading to neurodegeneration and parkinsonian phenotypes. Structural studies of the enzyme have established a trimeric architecture, comprising three identical protomers in which the active sites of each protease domain are sequestered to form a catalytically inactive complex. The mechanism by which enzyme function is regulated is not well understood. Using methyl transverse relaxation optimized spectroscopy (TROSY)-based solution NMR in concert with biochemical assays, a functional HtrA2 oligomerization/binding cycle has been established. In the absence of substrates, HtrA2 exchanges between a heretofore unobserved hexameric conformation and the canonical trimeric structure, with the hexamer showing much weaker affinity toward substrates. Both structures are substrate inaccessible, explaining their low basal activity in the absence of the binding of activator peptide. The binding of the activator peptide to each of the protomers of the trimer occurs with positive cooperativity and induces intrasubunit domain reorientations to expose the catalytic center, leading to increased proteolytic activity. Our data paint a picture of HtrA2 as a finely tuned, stress-protective enzyme whose activity can be modulated both by oligomerization and domain reorientation, with basal levels of catalysis kept low to avoid proteolysis of nontarget proteins. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Cooperativity; Human High temperature requirement A2; Ligand-binding thermodynamics and kinetics; Methyl transverse relaxation optimized spectroscopy; Trimer-hexamer equilibrium
语种	英语
scopus关键词	serine proteinase Omi; apoptosis; Article; controlled study; enzyme active site; enzyme conformation; Escherichia coli; kinetics; ligand binding; methyl transverse relaxation optimized spectroscopy; mitochondrion; nerve degeneration; nonhuman; nuclear magnetic resonance spectroscopy; oligomerization; phenotype; priority journal; protein degradation; protein function; protein homeostasis; signal transduction; thermodynamics
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180275
作者单位	Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada; Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
推荐引用方式 GB/T 7714	Toyama Y.,Harkness R.W.,Lee T.Y.T.,et al. Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR[J],2021,118(11).
APA	Toyama Y.,Harkness R.W.,Lee T.Y.T.,Maynes J.T.,&Kay L.E..(2021).Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR.Proceedings of the National Academy of Sciences of the United States of America,118(11).
MLA	Toyama Y.,et al."Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR".Proceedings of the National Academy of Sciences of the United States of America 118.11(2021).