エンドウ トシヤ   ENDO TOSHIYA
  遠藤 斗志也
   所属   京都産業大学  生命科学部 先端生命科学科
   職種   客員教授
言語種別 英語
発行・発表の年月 1994/10
形態種別 研究論文
査読 査読あり
標題 CHLOROPLAST PROTEIN IMPORT - CHLOROPLAST ENVELOPES AND THYLAKOIDS HAVE DIFFERENT ABILITIES TO UNFOLD PROTEINS
執筆形態 その他
掲載誌名 EUROPEAN JOURNAL OF BIOCHEMISTRY
出版社・発行元 WILEY-BLACKWELL
巻・号・頁 225(1),pp.403-409
著者・共著者 T ENDO,M KAWAKAMI,A GOTO,T AMERICA,P WEISBEEK,M NAKAI
概要 Proteins have to be at least partially unfolded upon passage through the biological membranes. Previous studies with a dihydrofolate reductase fusion protein containing a chloroplast transit peptide showed that stabilization of the tertiary structure of the fusion protein by binding of a ligand, methotrexate, failed to block its translocation across the envelopes, suggesting that chloroplast envelopes have strong activity to unfold proteins [America, T., Hageman, J., Guera, A., Rook, E, Archer, K., Keegstra, K. and Weisbeek, P (1994) Plant Mel. Biol. 24, 283-294]. In the present study, we have analyzed in vitro translocation of a fusion protein consisting of the entire plastocyanin precursor and dihydrofolate reductase across the chloroplast envelope membranes and the thylakoid membrane. In the presence of methotrexate, the fusion protein was imported into the stroma but its translocation across the thylakoid membrane was blocked. The fusion protein that bound to the envelope became susceptible to digestion by thermolysin. These results suggest that, while the envelope membranes can unfold the methotrexate-bound fusion protein to allow its passage, the thylakoid membrane cannot unfold the fusion protein that has re-bound to methotrexate in the stroma.
ISSN 0014-2956