Mitochondrial Lon of Saccharomyces cerevisiae is a ring-shaped protease with seven flexible subunits.
Lon (or La) is a soluble, homooligomeric ATP-dependent protease. Mass determination and cryoelectron microscopy of pure mitochondrial Lon from Saccharomyces cerevisiae identify Lon as a flexible ring-shaped heptamer. In the presence of ATP or 5'-adenylylimidodiphosphate, most of the rings are symmetric and resemble other ATP-driven machines that mediate folding and degradation of proteins. In the absence of nucleotides, most of the rings are distorted, with two adjacent subunits forming leg-like protrusions. These results suggest that asymmetric conformational changes serve to power processive unfolding and translocation of substrates to the active site of the Lon protease.
Stahlberg
H
H
M. E. Müller Institut, Biozentrum der Universität Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. stahlbergh@ubaclu.unibas.ch
Kutejová
E
E
Suda
K
K
Wolpensinger
B
B
Lustig
A
A
Schatz
G
G
Engel
A
A
Suzuki
C K
CK
D049069:ATP-Dependent Proteases; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008928:Mitochondria / Q000201:enzymology*; D017510:Protein Folding; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000648:ultrastructure; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases