An archaeal peptidase assembles into two different quaternary structures: A tetrahedron and a giant octahedron

Cellular proteolysis involves large oligomeric peptidases that play key roles in the regulation of many cellular processes. The cobalt-activated peptidase TET1 from the hyperthermophilic Archaea Pyrococcus horikoshii (PhTET1) was found to assemble as a 12-subunit tetrahedron and as a 24-subunit octa...

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Bibliographic Details
Published in:The Journal of biological chemistry 2006-11, Vol.281 (47), p.36327-36337
Main Authors: Schoehn, Guy, Vellieux, Frédéric M D, Asunción Durá, M, Receveur-Bréchot, Véronique, Fabry, Céline M S, Ruigrok, Rob W H, Ebel, Christine, Roussel, Alain, Franzetti, Bruno
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Aminopeptidases
Aminopeptidases - chemistry
Aminopeptidases - metabolism
Archaea
Biochemistry, Molecular Biology
Capsid
Capsid - chemistry
Catalysis
Cryoelectron Microscopy
Crystallography, X-Ray
Dimerization
Hydrolysis
Life Sciences
Models, Molecular
Molecular Sequence Data
Peptides
Peptides - chemistry
Protein Conformation
Protein Structure, Quaternary
Pyrococcus
Pyrococcus - enzymology
Pyrococcus horikoshii
Sequence Homology, Amino Acid
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Summary:Cellular proteolysis involves large oligomeric peptidases that play key roles in the regulation of many cellular processes. The cobalt-activated peptidase TET1 from the hyperthermophilic Archaea Pyrococcus horikoshii (PhTET1) was found to assemble as a 12-subunit tetrahedron and as a 24-subunit octahedral particle. Both quaternary structures were solved by combining x-ray crystallography and cryoelectron microscopy data. The internal organization of the PhTET1 particles reveals highly self-compartmentalized systems made of networks of access channels extended by vast catalytic chambers. The two edifices display aminopeptidase activity, and their organizations indicate substrate navigation mechanisms different from those described in other large peptidase complexes. Compared with the tetrahedron, the octahedron forms a more expanded hollow structure, representing a new type of giant peptidase complex. PhTET1 assembles into two different quaternary structures because of quasi-equivalent contacts that previously have only been identified in viral capsids.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M604417200