Sequence comparison among subunits of multicatalytic proteinase.
The cDNAs for a number of multicatalytic proteinase (MCP) subunits have been cloned, characterized, and their primary structures have been determined. The mechanism for how MCP demonstrates its multicatalytic nature, especially protease activities, however, is still obscure, since no sequences similar to known protease sequences can be found in the sequences of MCP subunits thus far determined. To explain this fact, we propose a structural model for MCP: MCP consists of two classes of subunits, structural and catalytic, and the structural subunits constitute a "test-tube"-like container in which the other catalytic subunits sit and react with substrate. Most of the observations thus far obtained can be explained easily by this hypothesis, although various other possibilities are not excluded.
Sorimachi
H
H
Department of Molecular Biology, Tokyo Metropolitan Institute of Medical Science, Japan.
Kawasaki
H
H
Tsukahara
T
T
Ishiura
S
S
Emori
Y
Y
Sugita
H
H
Suzuki
K
K
D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics*; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics*; D046988:Proteasome Endopeptidase Complex; D011487:Protein Conformation; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D009097:Multienzyme Complexes; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex