Camptosemin, a tetrameric lectin of Camptosema ellipticum: structural and functional analysis.
Lectins have been classified into a structurally diverse group of proteins that bind carbohydrates and glycoconjugates with high specificity. They are extremely useful molecules in the characterization of saccharides, as drug delivery mediators, and even as cellular surface makers. In this study, we present camptosemin, a new lectin from Camptosema ellipticum. It was characterized as an N-acetyl-D-galactosamine-binding homo-tetrameric lectin, with a molecular weight around 26 kDa/monomers. The monomers were stable over a wide range of pH values and exhibited pH-dependent oligomerization. Camptosemin promoted adhesion of breast cancer cells and hemagglutination, and both activities were inhibited by its binding of sugar. The stability and unfolding/folding behavior of this lectin was characterized using fluorescence and far-UV circular dichroism spectroscopies. The results indicate that chemical unfolding of camptosemin proceeds as a two-state monomer-tetramer process. In addition, small-angle X-ray scattering shows that camptosemin behaves as a soluble and stable homo-tetramer molecule in solution.
Batista
Fernanda A H
FA
Centro de Biotecnologia Molecular Estrutural (CBME), Instituto de Física de São Carlos (IFSC), Universidade de São Paulo (USP), São Carlos, Brazil.
Goto
Leandro S
LS
Garcia
Wanius
W
de Moraes
Derminda I
DI
de Oliveira Neto
Mario
M
Polikarpov
Igor
I
Cominetti
Marcia R
MR
Selistre-de-Araújo
Heloísa S
HS
Beltramini
Leila M
LM
Araújo
Ana Paula Ulian
AP
D000116:Acetylgalactosamine / Q000737:chemistry; D001943:Breast Neoplasms / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D007887:Fabaceae / Q000737:chemistry*; D005260:Female; D029624:Ferns; D006384:Hemagglutination; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D037121:Plant Lectins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D055550:Protein Stability; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction
D002241:Carbohydrates; D037121:Plant Lectins; D000116:Acetylgalactosamine