Đang chuẩn bị liên kết để tải về tài liệu:
Báo cáo khoa học: Protein transport in organelles: Protein transport into and across the thylakoid membrane

The chloroplast thylakoid is the most abundant membrane system in nat-ure, and is responsible for the critical processes of light capture, electron transport and photophosphorylation. Most of the resident proteins are imported from the cytosol and then transported into or across the thyla-koid membrane. | ỊFEBS Journal MINIREVIEW Protein transport in organelles Protein transport into and across the thylakoid membrane Cassie Aldridge Peter Cain and Colin Robinson Department of BiologicalSciences University of Warwick Coventry UK Keywords protein transport secretory pathway SRP Tat thylakoid twin-arginine Correspondence C. Robinson Department of Biological Sciences University of Warwick Coventry CV4 7AL UK Fax 44 2476 523568 Tel 44 2476 523557 E-mail colin.robinson@warwick.ac.uk These authors contributed equally to this work Received 5 August 2008 revised 25 November 2008 accepted 4 December 2008 The chloroplast thylakoid is the most abundant membrane system in nature and is responsible for the critical processes of light capture electron transport and photophosphorylation. Most of the resident proteins are imported from the cytosol and then transported into or across the thylakoid membrane. This minireview describes the multitude of pathways used for these proteins. We discuss the huge differences in the mechanisms involved in the secretory and twin-arginine translocase pathways used for the transport of proteins into the lumen with an emphasis on the differing substrate conformations and energy requirements. We also discuss the rationale for the use of two different systems for membrane protein insertion the signal recognition particle pathway and the so-called spontaneous pathway. The recent crystallization of a key chloroplast signal recognition particle component provides new insights into this rather unique form of signal recognition particle. doi 10.1111 j.1742-4658.2009.06875.x Introduction Chloroplasts are the site of photosynthesis and other important biochemical processes that are vital for the functioning of plant cells. They are believed to have arisen from a photosynthetic bacterium taken up by a primitive eukaryotic cell. Although some of the chloroplast proteome is encoded by the chloroplast genome during endosymbiosis most of the original prokaryotic