cDNA cloning of rat proteasome subunit RC7‐I, a homologue of yeast PRE1 essential for chymotrypsin‐like activity

作者：Chihiro Nishimura, Tomohiro Tamura, Fuminori Tokunaga, Keiji Tanaka, Akira Ichihara · 发表于：FEBS Letters · 年份：1993 · DOI：10.1016/0014-5793(93)80482-a · 被引用次数：11 · 研究领域：Ubiquitin and proteasome pathways、Glycosylation and Glycoproteins Research、Biochemical and Molecular Research

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.