title: Effects of selective cleavage of high-mannose-type glycans of Maackia amurensis leukoagglutinin on sialic acid-binding activity.
abstract: BACKGROUND
  Maackia amurensis leukoagglutinin (MAL) is a glycoprotein and sialic acid-binding lectin that is used widely in the detection and characterization of sialoglycoconjugates and human cancer cells. However, its N-linked glycan structure and role have yet to be determined.
  
  
  METHODS
  The N-linked glycans were analyzed using high-performance liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the secondary structure was investigated using circular dichroism analysis. A hemagglutination assay was performed. Furthermore, surface plasmon resonance analysis, and fluorescence microscopy and fluorescence-activated cell-sorting analysis were conducted to assess the sialoglycoprotein-binding ability and its usefulness in the detection of human breast cancer MCF-7 cells, respectively.
  
  
  RESULTS
  Analysis of the N-linked glycan structure of MAL confirmed the presence of eight glycans, comprising two α1,3-fucosylated paucimannosidic-type and six high-mannose-type glycans. Glycan analysis of MAL that had been treated with peptide N-glycosidase F (de-M-MAL) revealed that while the two α1,3-fucosylated paucimannosidic glycans remained attached following the treatment, the six high-mannose-type glycans had been completely cleaved from the original MAL. There were almost no secondary structural changes between MAL and de-M-MAL; however, the lectin activities exhibited by MAL, such as hemagglutination and binding to a sialoglycoprotein, were completely absent in de-M-MAL, and the ability to detect human breast cancer MCF-7 cells was 77% lower in de-M-MAL than in MAL.
  
  
  CONCLUSIONS
  The high-mannose-type glycans in intact MAL are closely associated with its lectin activities.
  
  
  CONCLUSIONS
  This is the first report of the N-linked glycan structure of MAL and the effect of high-mannose-type glycans on lectin activities.
authors.affiliation: Biotherapeutics and Glycomics Laboratory, College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea.
authors.forename: Byung Sun
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Biotherapeutics and Glycomics Laboratory, College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea.
authors.forename: Hye Seong
authors.initials: HS
authors.lastname: Hwang
authors.affiliation: Biotherapeutics and Glycomics Laboratory, College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea.
authors.forename: Heajin
authors.initials: H
authors.lastname: Park
authors.affiliation: Biotherapeutics and Glycomics Laboratory, College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea. Electronic address: hahyung@cau.ac.kr.
authors.forename: Ha Hyung
authors.initials: HH
authors.lastname: Kim
mesh_terms: D002942:Circular Dichroism; D060748:Fetuins / Q000378:metabolism; D006801:Humans; D008358:Mannose / Q000737:chemistry*; D010835:Phytohemagglutinins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D012794:Sialic Acids / Q000378:metabolism*; D020349:Surface Plasmon Resonance
chemical_list: D060748:Fetuins; D010835:Phytohemagglutinins; D011134:Polysaccharides; D012794:Sialic Acids; C100156:leukoagglutinins, plants; D008358:Mannose
keywords: Activity; High-mannose-type; Maackia amurensis lectin; N-linked glycan