title: Proteolytic cleavage at twin arginine residues affects structural and functional transitions of lupin seed 11S storage globulin.
abstract: The 11S storage globulin of white lupin seeds binds to a metal affinity chromatography matrix. Two unusual stretches of contiguous histidine residues, reminiscent of the multiple histidines forming metal binding motifs, at the C-terminal end of 11S globulin acidic chains were hypothesized as candidate elements responsible for the binding capacity. To prove this, the protein was incubated with a lupin seed endopeptidase previously shown to cleave at twin arginine motifs, recurrent in the sequence region of interest. Upon incubation with this enzyme, the loss of metal binding capacity paralleled that of the anti-his-tag reactive polypeptides. The recovered small proteolytic fragment was analyzed by mass spectrometry and N-terminal sequencing and found to correspond to the 24-mer region cleaved off at twin arginine residues and containing the natural his-tag-like region. Similarly, when lupin seeds were germinated for a few days, the his-tag containing 11S globulin chain was converted to a form devoid of such region, suggesting that this mechanism is a part of the natural degradatory process of the protein. The hypothesis that the ordered and controlled dismantling of storage proteins may generate peptide fragments with potential functional roles in plant ontogenesis is presented and discussed.
authors: Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
authors: Jessica
authors: J
authors: Capraro
authors: Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
authors: Fabio
authors: F
authors: Sessa
authors: Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
authors: Chiara
authors: C
authors: Magni
authors: Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
authors: Alessio
authors: A
authors: Scarafoni
authors: Department of Veterinary Science and Public Health, Università degli Studi di Milano, Milan, Italy.
authors: Elisa
authors: E
authors: Maffioli
authors: Department of Veterinary Science and Public Health, Università degli Studi di Milano, Milan, Italy.
authors: Gabriella
authors: G
authors: Tedeschi
authors: School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom.
authors: Ron R D
authors: RR
authors: Croy
authors: Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
authors: Marcello
authors: M
authors: Duranti
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry / Q000378:metabolism; D018525:Germination; D005916:Globulins / Q000737:chemistry / Q000378:metabolism*; D031297:Lupinus / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D059748:Proteolysis; D012639:Seeds / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005916:Globulins; D010940:Plant Proteins; D001120:Arginine