Expression of functional hexahistidine-tagged ricin B in tobacco.
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.
Reed
Deborah G
DG
Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0331, USA.
Nopo-Olazabal
Luis H
LH
Funk
Vanessa
V
Woffenden
Bonnie J
BJ
Reidy
Michael J
MJ
Dolan
Maureen C
MC
Cramer
Carole L
CL
Medina-Bolivar
Fabricio
F
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
C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011994:Recombinant Proteins; D006639:Histidine; D012276:Ricin