title: Potato lectin: a modular protein sharing sequence similarities with the extensin family, the hevein lectin family, and snake venom disintegrins (platelet aggregation inhibitors).
abstract: Potato (Solanum tuberosum) lectin, is a chimeric chitin-binding protein comprised of a lectin domain fused to a hydroxyproline-rich glycoprotein domain. Here peptide sequence information from both domains is presented. A partial sequence of a major tryptic peptide T2: Leu-Pro-Ser-Hyp-Hyp-Hyp-Hyp-Hyp-Hyp-(His)-Hyp-Ser-Hyp-Hyp- Hyp-Hyp-Ser-Hyp-Hyp-Ser-Hyp-Hyp-Hyp-Hyp-Ser-Hyp-Hyp- was similar to the 'P3' type extensin major repetitive sequence: Ser-Hyp-Hyp-Hyp-Hyp-Ser-Hyp-Ser-Hyp-Hyp-Hyp-Hyp- suggesting common evolutionary origins for the extensins and the hydroxyproline-rich glycoprotein (HRGP) domain of potato lectin. Furthermore, alignment of three chymotryptic peptides from potato lectin, C1: Cys-Gly-Thr-Thr-Ser-Asp-Tyr, C2: Cys-Ser-Pro-Gly-Tyr, and C8: Thr-Gly-Glu-Cys-Cys-Ser-Ile with similar sequences from the hevein lectin family indicates that they have homologous chitin-binding domains, and hence have common evolutionary origins. Finally, all plant chitin-binding domains examined bore a remarkable sequence similarity, particularly in the spacing of Cys residues, to the disintegrins (platelet aggregation inhibitors) which occur in crotalid and viperid snake venoms. As such, sequence similarities not only identify potato lectin as a member of both the hevein and extensin families of plant proteins, but also suggest that an archetypal polypeptide module gave rise to both the plant chitin-binding domain and the reptile disintegrins.
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens 30602.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kieliszewski
authors.forename: A M
authors.initials: AM
authors.lastname: Showalter
authors.forename: J F
authors.initials: JF
authors.lastname: Leykam
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D023181:Antimicrobial Cationic Peptides; D002686:Chitin / Q000378:metabolism; D019483:Disintegrins; D006023:Glycoproteins / Q000235:genetics; D006909:Hydroxyproline / Q000032:analysis; D037102:Lectins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000302:isolation & purification; D010455:Peptides / Q000235:genetics; D037121:Plant Lectins; D010940:Plant Proteins / Q000235:genetics; D010975:Platelet Aggregation Inhibitors; D016415:Sequence Alignment; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012910:Snake Venoms / Q000737:chemistry
chemical_list: D000596:Amino Acids; D023181:Antimicrobial Cationic Peptides; D019483:Disintegrins; D006023:Glycoproteins; D037102:Lectins; D010446:Peptide Fragments; D010455:Peptides; D037121:Plant Lectins; D010940:Plant Proteins; D010975:Platelet Aggregation Inhibitors; D012910:Snake Venoms; C005488:extensin protein, plant; C041202:potato lectin; C045875:hevein; D002686:Chitin; D006909:Hydroxyproline