A remodeling system of the 3'-sulfo-Lewis a and 3'-sulfo-Lewis x epitopes.
It has been reported that the chemically synthesized 3'-sulfo-Le(a) and 3'-sulfo-Le(x) epitopes have a high potential as a ligand for selectins. To elucidate the physiological functions of 3'-sulfated Lewis epitopes, a remodeling system was developed using a combination of a betaGal-3-O-sulfotransferase GP3ST, hitherto known alpha1,3/1,4-fucosyltransferases (FucT-III, IV, V, VI, VII, and IX) and arylsulfatase A. The pyridylaminated (PA) lacto-N-tetraose (Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc) was first converted to 3'-sulfolacto-N-fucopentaose II (sulfo-3Galbeta1-3(Fucalpha1-4)GlcNAcbeta1-3Galbeta1-4Glc)-PA by sequential reactions with GP3ST and FucT-III. The 3'-sulfolacto-N-fucopentaose III (sulfo-3Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4Glc)-PA was then synthesized from lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc)-PA by GP3ST and FucT-III, -IV, -V, -VI, -VII, or -IX in a similar manner. The substrate specificity for the 3'-sulfated acceptor of the alpha1,3-fucosyltransferases was considerably different from that for the non-substituted and 3'-sialylated varieties. When the GP3ST gene was introduced into A549 and Chinese hamster ovary cells expressing FucT-III, they began to express 3'-sulfo-Le(a) and 3'-sulfo-Le(x) epitopes, respectively, suggesting that GP3ST is responsible for their biosynthesis in vivo. The expression of the 3'-sialyl-Le(x) epitope on Chinese hamster ovary cells was attenuated by the introduction of GP3ST gene, indicating that GP3ST and alpha2,3-sialyltransferase compete for the common Galbeta1-4GlcNAc-R oligosaccharides. Last, arylsulfatase A, which is a lysosomal hydrolase that catalyzes the desulfation of 3-O-sulfogalactosyl residues in glycolipids, was found to hydrolyze the sulfate ester bond on the 3'-sulfo-Le(x) (type 2 chain) but not that on the 3'-sulfo-Le(a) (type 1 chain). The present remodeling system might be of potential use as a tool for the study of the physiological roles of 3'-sulfated Lewis epitopes, including interaction with selectins.
Ikeda
N
N
Department of Biochemistry and Department of Surgery, Osaka University Medical School, Suita, Osaka 565-0871, Japan.
Eguchi
H
H
Nishihara
S
S
Narimatsu
H
H
Kannagi
R
R
Irimura
T
T
Ohta
M
M
Matsuda
H
H
Taniguchi
N
N
Honke
K
K
D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D000939:Epitopes / Q000737:chemistry*; D005434:Flow Cytometry; D005647:Fucosyltransferases / Q000737:chemistry; D006801:Humans; D007983:Lewis Blood Group Antigens; D016256:Lewis X Antigen / Q000031:analogs & derivatives; D008024:Ligands; D008856:Microscopy, Fluorescence; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D014162:Transfection
C402829:3-sulfated Lewis x; D000939:Epitopes; D007983:Lewis Blood Group Antigens; D016256:Lewis X Antigen; D008024:Ligands; D009844:Oligosaccharides; C116504:sulfo-Lewis(a); D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase