The proteasome from Thermoplasma acidophilum is neither a cysteine nor a serine protease

FEBS Letters

Baumeister, Wolfgang¹  Seemüller, Erika¹  Lupas, Andrei¹  Zwickl, Peter¹  Zühl, Frank¹ 

[1] Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany

关键词: Proteasome;    Proteolysis;    Archaebacterium;    Thermoplasma acidophilum;   

DOI  :  10.1016/0014-5793(95)00036-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The 20 S proteasome, found in eukaryotes and in the archaebacterium Thermoplasma acidophilum, forms the proteolytic core of the 26 S proteasome which is the central protease of the non-lysosomal protein degradation pathway. Inhibitor studies have indicated that the 20 S proteasome may be an unusual type of cysteine or serine protease and a recent study of the Thermoplasma β subunit has indicated that it carries the proteolytic activity. We have attempted to obtain information on the nature of the active site by mutating the only cysteine, both histidines and two completely conserved aspartates in the archaebacterial complex as well as all serines of the β subunit, without decreasing the catalytic activity of the enzyme to any significant extent. Indeed, mutation of the conserved aspartate in the β subunit increased the activity of the proteasome threefold. We conclude that the proteasome is not a cysteine or serine protease.

【 授权许可】

Unknown