Sequence analysis and protein import studies of an outer chloroplast envelope polypeptide

Salomon, Michael; Fischer, Karsten; Flügge, Ulf-Ingo and Soll, Jürgen (August 1990): Sequence analysis and protein import studies of an outer chloroplast envelope polypeptide. In: Proceedings of the National Academy of Science of the USA, Vol. 87, No. 15: pp. 5778-5782

Abstract

A chloroplast outer envelope membrane protein was cloned and sequenced and from the sequence it was possible to deduce a polypeptide of 6.7 kDa. It has only one membrane-spanning region; the C terminus extends into the cytosol, whereas the N terminus is exposed to the space between the two envelope membranes. The protein was synthesized in an in vitro transcription-translation system to study its routing into isolated chloroplasts. The import studies revealed that the 6.7-kDa protein followed a different and heretofore undescribed translocation pathway in the respect that (i) it does not have a cleavable transit sequence, (ii) it does not require ATP hydrolysis for import, and (iii) protease-sensitive components that are responsible for recognition of precursor proteins destined for the inside of the chloroplasts are not involved in routing the 6.7-kDa polypeptide to the outer chloroplast envelope.

• Item Type: Journal article
• Faculties: Biology
• Subjects: 500 Science > 570 Life sciences; biology
• Language: English