title: cDNA cloning of rat proteasome subunit RC7-I, a homologue of yeast PRE1 essential for chymotrypsin-like activity.
abstract: The nucleotide sequence of a cDNA that encodes a new subunit, named RC7-I, of the 20 S proteasome of rat hepatoma cells has been determined. The polypeptide predicted from the open reading frame consists of 201 amino acid residues with a calculated molecular weight of 22,912 and isoelectric point of 7.25. Approximately 80% of the partial amino acid sequences of several fragments of RC7-I, determined by protein chemical analyses, were found to be in excellent accordance with those deduced from the cDNA sequence. Computer analysis showed that RC7-I belongs to the beta-type subgroup of proteasomes with similarity to the beta-subunit of the archaebacterial proteasome, differing clearing from alpha-type subunits of the proteasome gene family. The overall structure of RC7-I was found to be homologous to that of yeast PRE1, which is necessary for chymotryptic activity.
authors.affiliation: Laboratory of Applied Toxicology, Nippon Kayaku Co. Ltd., Gunma, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Nishimura
authors.forename: T
authors.initials: T
authors.lastname: Tamura
authors.forename: F
authors.initials: F
authors.lastname: Tokunaga
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Ichihara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002918:Chymotrypsin / Q000378:metabolism*; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary; D005656:Fungal Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013822:Thermoplasma / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D002918:Chymotrypsin; D003546:Cysteine Endopeptidases; C083706:PRE1 protein, S cerevisiae; D046988:Proteasome Endopeptidase Complex