title: H-3, a new lectin from the marine sponge Haliclona caerulea: purification and mass spectrometric characterization.
abstract: A new lectin from the marine sponge Haliclona caerulea (H-3) was isolated using a combination of hydrophobic interaction chromatography and ion-exchange chromatography. H-3 is a protein with three distinct bands on SDS-PAGE: 9 kDa, 16 kDa and 18 kDa. Nevertheless, on gel filtration and N-PAGE, H-3 showed a symmetrical peak and a unique band, respectively. Hemagglutinating activity of H-3 was stable at neutral pH and temperatures up to 60 °C. N-Acetylgalactosamine and porcine stomach mucin were the most potent inhibitors of H-3. Primary structure of the lectin was determined using tandem mass spectrometry, and it showed no similarity to any members of the animal lectin families. Top down fragmentation revealed some posttranslational modifications in H-3, including glycosylation. The glycan composition of H-3 was determined, and its structure was predicted. Furthermore, H-3 is a blue protein, binding to a chromophore(-597) by weak interactions, and this is the first time that the interaction between one lectin and a natural chromophore has been shown.
authors.affiliation: Laboratório de Moléculas Biologicamente Ativas - BioMol-Lab, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Campus do Pici, s/n bloco 907, 60440-970 Fortaleza, Ceará, Brazil(1).
authors.forename: Rômulo Farias
authors.initials: RF
authors.lastname: Carneiro
authors.forename: Arthur Alves
authors.initials: AA
authors.lastname: de Melo
authors.forename: Alexandra Sampaio
authors.initials: AS
authors.lastname: de Almeida
authors.forename: Raniere da Mata
authors.initials: Rda M
authors.lastname: Moura
authors.forename: Renata Pinheiro
authors.initials: RP
authors.lastname: Chaves
authors.forename: Bruno Lopes
authors.initials: BL
authors.lastname: de Sousa
authors.forename: Kyria Santiago
authors.initials: KS
authors.lastname: do Nascimento
authors.forename: Silvana Saker
authors.initials: SS
authors.lastname: Sampaio
authors.forename: João Paulo Matos Santos
authors.initials: JP
authors.lastname: Lima
authors.forename: Benildo Sousa
authors.initials: BS
authors.lastname: Cavada
authors.forename: Celso Shiniti
authors.initials: CS
authors.lastname: Nagano
authors.forename: Alexandre Holanda
authors.initials: AH
authors.lastname: Sampaio
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D006031:Glycosylation; D047129:Haliclona / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D013058:Mass Spectrometry / Q000379:methods
chemical_list: D037102:Lectins
keywords: Chromophore; Glycosylation; Lectin; Primary structure; Sponge