title: Topological properties of the triple gene block protein 2 of Bamboo mosaic virus.
abstract: The triple gene block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) has been proposed to be a transmembrane protein; however, its features remain unclear. Here, we used biochemical approaches to determine its topological properties. Our data reveal that TGBp2 is mainly associated with the endoplasmic reticulum membrane. The resistance of TGBp2 in proteoliposomes, prepared from both the BaMV-infected tissues and in vitro reconstitution system, to both chemical extraction and trypsin digestion confirmed that it is indeed an integral membrane protein. On the basis of the minor change in the size of the major stable TGBp2-derived tryptic fragment from the monomeric TGBp2, as well as the sensitivity of the cysteine residues at the C-terminal tail of TGBp2 to maleimide modification, we suggest that TGBp2 adopts a topology with both its short N- and C-terminal tails exposed to the outer surface of the endoplasmic reticulum. Moreover, TGBp2 is able to self-assemble as revealed by the significant increase in multimeric TGBp2 when the TGBp2-containing proteoliposomes were treated with chemical crosslinker or oxidation agent.
authors.affiliation: Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China.
authors.forename: Hsiu-Ting
authors.initials: HT
authors.lastname: Hsu
authors.forename: Yuan-Lin
authors.initials: YL
authors.lastname: Chou
authors.forename: Yang-Hao
authors.initials: YH
authors.lastname: Tseng
authors.forename: Yu-Hsing
authors.initials: YH
authors.lastname: Lin
authors.forename: Tzung-Min
authors.initials: TM
authors.lastname: Lin
authors.forename: Na-Sheng
authors.initials: NS
authors.lastname: Lin
authors.forename: Yau-Heiu
authors.initials: YH
authors.lastname: Hsu
authors.forename: Ban-Yang
authors.initials: BY
authors.lastname: Chang
mesh_terms: D002462:Cell Membrane / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D059828:Plant Cells; D010944:Plants / Q000821:virology; D017863:Potexvirus / Q000502:physiology*; D011510:Proteolipids / Q000737:chemistry; D014357:Trypsin / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D011510:Proteolipids; D014764:Viral Proteins; C020485:proteoliposomes; D014357:Trypsin