A Lon-Like Protease with No ATP-Powered Unfolding Activity
In: PLoS ONE, Jg. 7 (2012-07-06), Heft 7, p e40226, S. e40226
Online
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Zugriff:
Lon proteases are a family of ATP-dependent proteases involved in protein quality control, with a unique proteolytic domain and an AAA(+) (ATPases associated with various cellular activities) module accommodated within a single polypeptide chain. They were classified into two types as either the ubiquitous soluble LonA or membrane-inserted archaeal LonB. In addition to the energy-dependent forms, a number of medically and ecologically important groups of bacteria encode a third type of Lon-like proteins in which the conserved proteolytic domain is fused to a large N-terminal fragment lacking canonical AAA(+) motifs. Here we showed that these Lon-like proteases formed a clade distinct from LonA and LonB. Characterization of one such Lon-like protease from Meiothermus taiwanensis indicated that it formed a hexameric assembly with a hollow chamber similar to LonA/B. The enzyme was devoid of ATPase activity but retained an ability to bind symmetrically six nucleotides per hexamer; accordingly, structure-based alignment suggested possible existence of a non-functional AAA-like domain. The enzyme degraded unstructured or unfolded protein and peptide substrates, but not well-folded proteins, in ATP-independent manner. These results highlight a new type of Lon proteases that may be involved in breakdown of excessive damage or unfolded proteins during stress conditions without consumption of energy.
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A Lon-Like Protease with No ATP-Powered Unfolding Activity
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Autor/in / Beteiligte Person: | Wu, Shih-Hsiung ; Chang, Chung-I ; Chang, Wei-Hau ; Kuo, Chiao-I ; Wu, Wan-Ling ; Liao, Jiahn-Haur ; Lin, Yu-Ching ; Yang, Chen-Yui ; Lin, Li-Hua ; Lin, Yen-Chen ; Huang, Ya-Yi ; Liaw, Yen-Chywan |
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Zeitschrift: | PLoS ONE, Jg. 7 (2012-07-06), Heft 7, p e40226, S. e40226 |
Veröffentlichung: | Public Library of Science (PLoS), 2012 |
Medientyp: | unknown |
ISSN: | 1932-6203 (print) |
DOI: | 10.1371/journal.pone.0040226 |
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