A giant protease with a twist: the TPP II complex from Drosophila studied by electron microscopy.
EMBO J
; 21(22): 5979-84, 2002 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-12426370
Tripeptidyl peptidase II (TPP II) is an exopeptidase of the subtilisin type of serine proteases that is thought to act downstream of the proteasome in the ubiquitin-proteasome pathway. Recently, a key role in a pathway parallel to the ubiquitin-proteasome pathway has been ascribed to TPP II, which forms a giant protease complex in mammalian cells. Here, we report the 900-fold purification of TPP II from Drosophila eggs and demonstrate via cryo-electron microscopy that TPP II from Drosophila melanogaster also forms a giant protease complex. The presented three-dimensional reconstruction of the 57 x 27 nm TPP II complex at 3.3 nm resolution reveals that the 150 kDa subunits form a superstructure composed of two segmented and twisted strands. Each strand is 12.5 nm in width and composed of 11 segments that enclose a central channel.
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Base de dados:
MEDLINE
Assunto principal:
Serina Endopeptidases
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Microscopia Crioeletrônica
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Proteínas de Drosophila
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article