A Novel Core Fucose-specific Lectin from the Mushroom Pholiota squarrosa

• DOI: 10.1074/jbc.m111.327692
• Publication Date: 2012-08-08T00:28:08Z
• Authors: Yuka Kobayashi; Hiroaki Tateno; Hideo Dohra; Kenta Moriwaki; Eiji Miyoshi; Jun Hirabayashi; Hirokazu Kawagishi
• Keywords: 0301 basic medicine; Carcinoma, Hepatocellular; Protein Stability; Liver Neoplasms; Molecular Sequence Data; Oligosaccharides; 3. Good health; Fungal Proteins; 03 medical and health sciences; Antigens, Neoplasm; Cell Line, Tumor; Lectins; Pholiota; Humans; Amino Acid Sequence; Fucose; Protein Binding

Fucα1-6 oligosaccharide has a variety of biological functions and serves as a biomarker for hepatocellular carcinoma because of the elevated presence of fucosylated α-fetoprotein (AFP) in this type of cancer. In this study we purified a novel Fucα1-6-specific lectin from the mushroom Pholiota squarrosa by ion-exchange chromatography and affinity chromatography on thyroglobulin-agarose. The purified lectin was designated as PhoSL (P. squarrosa lectin). SDS-PAGE, MALDI-TOF mass spectrometry, and N-terminal amino acid sequencing indicate that PhoSL has a molecular mass of 4.5 kDa and consists of 40 amino acids (NH(2)-APVPVTKLVCDGDTYKCTAYLDFGDGRWVAQWDTNVFHTG-OH). Isoelectric focusing of the lectin showed bands near pI 4.0. The lectin activity was stable between pH 2.0 and 11.0 and at temperatures ranging from 0 to 100 °C for incubation times of 30 min. When PhoSL was investigated with frontal affinity chromatography using 132 pyridylaminated oligosaccharides, it was found that the lectin binds only to core α1-6-fucosylated N-glycans and not to other types of fucosylated oligosaccharides, such as α1-2-, α1-3-, and α1-4-fucosylated glycans. Furthermore, PhoSL bound to α1-6-fucosylated AFP but not to non-fucosylated AFP. In addition, PhoSL was able to demonstrate the differential expression of α1-6 fucosylation between primary and metastatic colon cancer tissues. Thus, PhoSL will be a promising tool for analyzing the biological functions of α1-6 fucosylation and evaluating Fucα1-6 oligosaccharides as cancer biomarkers.