title: Isolation and characterization of a new agglutinin from the red marine alga Hypnea cervicornis J. Agardh.
abstract: The biochemical characterization of a new lectin (Hypnea cervicornis agglutinin or HCA) isolated from the Brazilian red alga H. cervicornis is reported. The haemagglutinating activity of the lectin was only inhibited by the glycoprotein porcine stomach mucin at a minimum inhibitory concentration of 19 microg x mL(-1). No haemagglutination inhibition was detected after the addition of simple sugars. The MALDI-TOF molecular masses of native and reduced and carbamidomethylated HCA were, respectively, 9196.6 Da and 9988.2 Da, indicating that the primary structure of the protein is crosslinked by 7 disulfide bonds. This unusual structural feature among lectins, along with its N-terminal sequence and amino-acid composition, clearly shows that HCA belongs to a protein family distinct from the isolectins Hypnin A1 and A2 isolated from the related Japanese alga Hypnea japonica. On the other hand, HCA displayed a high degree of similarity to the agglutinin from the Brazilian species Hypnea musciformis. Our data indicate the occurrence of structural diversity among lectins of closely related species living in distant ecosystems, i.e., the Pacific coast of Japan and the Atlantic coast of Brazil, and support the hypothesis that the lectin content (lectinome) might serve as a biomarker for taxonomical purposes.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza-Ceará, Brazil.
authors.forename: K S
authors.initials: KS
authors.lastname: Nascimento
authors.forename: C S
authors.initials: CS
authors.lastname: Nagano
authors.forename: E V
authors.initials: EV
authors.lastname: Nunes
authors.forename: R F
authors.initials: RF
authors.lastname: Rodrigues
authors.forename: G V
authors.initials: GV
authors.lastname: Goersch
authors.forename: B S
authors.initials: BS
authors.lastname: Cavada
authors.forename: J J
authors.initials: JJ
authors.lastname: Calvete
authors.forename: S
authors.initials: S
authors.lastname: Saker-Sampaio
authors.forename: W R L
authors.initials: WR
authors.lastname: Farias
authors.forename: A H
authors.initials: AH
authors.lastname: Sampaio
mesh_terms: D000373:Agglutinins / Q000737:chemistry* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000596:Amino Acids; D000818:Animals; D002852:Chromatography, Ion Exchange; D006384:Hemagglutination; D006386:Hemagglutination Tests; D008969:Molecular Sequence Data; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D000373:Agglutinins; D000596:Amino Acids