Caenorhabditis elegans galectins LEC-1-LEC-11: structural features and sugar-binding properties.
Galectins form a large family of beta-galactoside-binding proteins in metazoa and fungi. This report presents a comparative study of the functions of potential galectin genes found in the genome database of Caenorhabditis elegans. We isolated full-length cDNAs of eight potential galectin genes (lec-2-5 and 8-11) from a lambdaZAP cDNA library. Among them, lec-2-5 were found to encode 31-35-kDa polypeptides containing two carbohydrate-recognition domains similar to the previously characterized lec-1, whereas lec-8-11 were found to encode 16-27-kDa polypeptides containing a single carbohydrate-recognition domain and a C-terminal tail of unknown function. Recombinant proteins corresponding to lec-1-4, -6, and 8-10 were expressed in Escherichia coli, and their sugar-binding properties were assessed. Analysis using affinity adsorbents with various beta-galactosides, i.e., N-acetyllactosamine (Galbeta1-4GlcNAc), lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc), and asialofetuin, demonstrated that LEC-1-4, -6, and -10 have a significant affinity for beta-galactosides, while the others have a relatively lower affinity. These results indicate that the integrity of key amino acid residues responsible for recognition of lactose (Galbeta1-4Glc) or N-acetyllactosamine in vertebrate galectins is also required in C. elegans galectins. However, analysis of their fine oligosaccharide-binding properties by frontal affinity chromatography suggests their divergence towards more specialized functions.
Nemoto-Sasaki
Yoko
Y
Department of Biological Chemistry, Teikyo University School of Pharmaceutical Sciences, 1091-1 Suarashi, Sagamiko, Sagamihara, Kanagawa 229-0195, Japan. ynsasaki@pharm.teikyo-u.ac.jp
Hayama
Ko
K
Ohya
Hiroyuki
H
Arata
Yoichiro
Y
Kaneko
Mika Kato
MK
Saitou
Naruya
N
Hirabayashi
Jun
J
Kasai
Ken-ichi
K
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary; D037161:Galectins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017238:Genes, Helminth; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D021382:Protein Sorting Signals; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
D018076:DNA, Complementary; D037161:Galectins; D009844:Oligosaccharides; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D011994:Recombinant Proteins