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Crystal structure of the N-terminal fragment (residue 1-291) of LonA protease from Meiothermus taiwanensisCrystal structure of the N-terminal fragment (residue 1-291) of LonA protease from Meiothermus taiwanensis
Structural highlights
FunctionA0A059VAZ3_9DEIN ATP-dependent serine protease that mediates the selective degradation of mutant and abnormal proteins as well as certain short-lived regulatory proteins. Required for cellular homeostasis and for survival from DNA damage and developmental changes induced by stress. Degrades polypeptides processively to yield small peptide fragments that are 5 to 10 amino acids long. Binds to DNA in a double-stranded, site-specific manner.[HAMAP-Rule:MF_01973] Publication Abstract from PubMedThe Lon AAA+ protease (LonA) is a ubiquitous ATP-dependent proteolytic machine, which selectively degrades damaged proteins or native proteins carrying exposed motifs (degrons). Here we characterize the structural basis for substrate recognition and discrimination by the N-terminal domain (NTD) of LonA. The results reveal that the six NTDs are attached to the hexameric LonA chamber by flexible linkers such that the formers tumble independently of the latter. Further spectral analyses show that the NTD selectively interacts with unfolded proteins, protein aggregates, and degron-tagged proteins by two hydrophobic patches of its N-lobe, but not intrinsically disordered substrate, alpha-casein. Moreover, the NTD selectively binds to protein substrates when they are thermally induced to adopt unfolded conformations. Collectively, our findings demonstrate that NTDs enable LonA to perform protein quality control to selectively degrade proteins in damaged states and suggest that substrate discrimination and selective degradation by LonA are mediated by multiple NTD interactions. Molecular insights into substrate recognition and discrimination by the N-terminal domain of Lon AAA+ protease.,Tzeng SR, Tseng YC, Lin CC, Hsu CY, Huang SJ, Kuo YT, Chang CI Elife. 2021 Apr 30;10. pii: 64056. doi: 10.7554/eLife.64056. PMID:33929321[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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