title: Novel protein from Labramia bojeri A. DC. seeds homologue to Kunitz-type trypsin inhibitor with lectin-like properties.
abstract: This study starts by isolating and characterizing the first protein from Labramia bojeri seeds, which belong to the Sapotaceae family. The purified lectin analyzed by SDS-PAGE with and without beta-mercaptoethanol shows two protein bands (M(r) = 19 and 20 kDa), which cannot be resolved. Protein bands have shown similar characteristics as molecular masses, determined by gel filtration and native gel; N-terminal sequences presented a difference in their isoelectric points. We have suggested that those protein bands might be variants of the protein named Labramin. The sequence database search has shown that the N-terminal sequence of Labramin presented a high degree of homology to Kunitz-type trypsin inhibitor (82-52%) despite no trypsin inhibition activity detection. The lectin-like form from Labramin was better inhibited by glycoproteins and has also presented growth inhibition of the fungus Colletotrichum lindemuthianum and the yeast Saccharomyces cerevisiae, but it has not presented an apparent effect on Fusarium oxysporum.
authors.affiliation: Laboratório de Purificação de Proteínas e suas Funções Biológicas, Departamento de Ciências Naturais, Universidade Federal de Mato Grosso do Sul, CP 210, CEP 79603-011, Três Lagoas, MS, Brazil. biopplant@terra.com.br
authors.forename: Maria Lígia Rodrigues
authors.initials: ML
authors.lastname: Macedo
authors.forename: Maria das Graças Machado
authors.initials: Md
authors.lastname: Freire
authors.forename: Ludmilla T D Mendes
authors.initials: LT
authors.lastname: Martins
authors.forename: Diego S T
authors.initials: DS
authors.lastname: Martinez
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
authors.forename: Marcos B
authors.initials: MB
authors.lastname: Smolka
authors.forename: Marcos H
authors.initials: MH
authors.lastname: Toyama
authors.forename: Sérgio
authors.initials: S
authors.lastname: Marangoni
authors.forename: Luana Cassandra B B
authors.initials: LC
authors.lastname: Coelho
mesh_terms: D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005659:Fungicides, Industrial / Q000494:pharmacology; D006384:Hemagglutination; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification*; D037121:Plant Lectins / Q000737:chemistry / Q000302:isolation & purification*; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification*; D029632:Sapotaceae / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*
chemical_list: D005659:Fungicides, Industrial; C053865:Kunitz-type protease inhibitor, plant; D010455:Peptides; D037121:Plant Lectins; D010940:Plant Proteins