Electron microscopy and image analysis reveal common principles of organization in two large protein complexes: groEL-type proteins and proteasomes.
In an attempt to settle the question of whether the multicatalytic proteinase or proteasome exist in all three kingdoms of life--eukaryotes, archaebacteria, and eubacteria--we have undertaken a search for them in the eubacterium Comamonas acidovorans. We have, in fact, isolated and purified a cylinder-shaped particle. However, according to various structural and biochemical criteria this turned out to be more reminiscent of the groEL protein from Escherichia coli and its homologs than to proteasomes of eukaryotic or archaebacterial origin. N-terminal sequencing provided definite proof for its belonging to this family of molecular chaperonins. Image analysis of electron micrographs revealed that the C. acidovorans groEL-like protein and proteasomes in spite of their significantly different dimensions have certain principles of organization in common.
Zwickl
P
P
Max-Planck-Institut für Biochemie, Federal Republic of Germany.
Pfeifer
G
G
Lottspeich
F
F
Kopp
F
F
Dahlmann
B
B
Baumeister
W
W
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure*; D018834:Chaperonin 60; D018833:Chaperonins; D002850:Chromatography, Gel; D003546:Cysteine Endopeptidases / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000648:ultrastructure*; D005051:Eubacterium / Q000648:ultrastructure*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000648:ultrastructure*; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000737:chemistry*; D012689:Sequence Homology, Nucleic Acid
D001426:Bacterial Proteins; D018834:Chaperonin 60; D006360:Heat-Shock Proteins; D009097:Multienzyme Complexes; D011506:Proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D018833:Chaperonins