Document Detail

Characterization of the proteasome from the extremely halophilic archaeon Haloarcula marismortui.
MedLine Citation:
PMID:  15803659     Owner:  NLM     Status:  MEDLINE    
A 20S proteasome, comprising two subunits alpha and beta, was purified from the extreme halophilic archaeon Haloarcula marismortui, which grows only in saturated salt conditions. The three-dimensional reconstruction of the H. marismortui proteasome (Hm proteasome), obtained from negatively stained electron micrographs, is virtually identical to the structure of a thermophilic proteasome filtered to the same resolution. The stability of the Hm proteasome was found to be less salt-dependent than that of other halophilic enzymes previously described. The proteolytic activity of the Hm proteasome was investigated using the malate dehydrogenase from H. marismortui (HmMalDH) as a model substrate. The HmMalDH denatures when the salt concentration is decreased below 2 M. Under these conditions, the proteasome efficiently cleaves HmMalDH during its denaturation process, but the fully denatured HmMalDH is poorly degraded. These in vitro experiments show that, at low salt concentrations, the 20S proteasome from halophilic archaea eliminates a misfolded protein.
B Franzetti; G Schoehn; D Garcia; R W H Ruigrok; G Zaccai
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Archaea (Vancouver, B.C.)     Volume:  1     ISSN:  1472-3646     ISO Abbreviation:  Archaea     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2005-04-04     Completed Date:  2005-04-21     Revised Date:  2010-09-20    
Medline Journal Info:
Nlm Unique ID:  101142614     Medline TA:  Archaea     Country:  Canada    
Other Details:
Languages:  eng     Pagination:  53-61     Citation Subset:  IM    
Institut de Biologie Structurale, CNRS-CEA, 41 rue J. Horowitz, 38027 Grenoble cedex 1, France.
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MeSH Terms
Archaeal Proteins / chemistry,  isolation & purification,  metabolism
Enzyme Stability
Haloarcula marismortui / enzymology*
Proteasome Endopeptidase Complex / chemistry*,  isolation & purification,  metabolism*
Sodium Chloride / pharmacology
Reg. No./Substance:
0/Archaeal Proteins; 7647-14-5/Sodium Chloride; EC Endopeptidase Complex

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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