title: Expression of functional hexahistidine-tagged ricin B in tobacco.
abstract: Ricin B (RTB), the lectin subunit of ricin, shows promise as an effective mucosal adjuvant and carrier for use in humans. In order to obtain a recombinant plant source of RTB that is devoid of the toxic ricin A subunit, we expressed RTB in Nicotiana tabacum. RTB was engineered with an N-terminal hexahistidine tag (His-RTB), which may affect protein stability. Lactose-affinity purification of His-RTB from leaves yielded three major glycosylated products of 32, 33.5 and 35 kDa. Their identity as RTB was verified by mass spectrometry and immunoblotting with anti-ricin antibodies. Functionality of His-RTB was confirmed by binding to asialofetuin, lactose and galactose.
authors.affiliation: Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0331, USA.
authors.forename: Deborah G
authors.initials: DG
authors.lastname: Reed
authors.forename: Luis H
authors.initials: LH
authors.lastname: Nopo-Olazabal
authors.forename: Vanessa
authors.initials: V
authors.lastname: Funk
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: Woffenden
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Reidy
authors.forename: Maureen C
authors.initials: MC
authors.lastname: Dolan
authors.forename: Carole L
authors.initials: CL
authors.lastname: Cramer
authors.forename: Fabricio
authors.initials: F
authors.lastname: Medina-Bolivar
mesh_terms: D015870:Gene Expression / Q000502:physiology*; D006639:Histidine / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000096:biosynthesis; D012276:Ricin / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
chemical_list: C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011994:Recombinant Proteins; D006639:Histidine; D012276:Ricin