Oligosaccharide sequence of human breast cancer cell heparan sulfate with high affinity for laminin.
Laminin-1 is a basement membrane glycoprotein implicated in tumor-host adhesion, which involves the cell-binding domain(s) of laminin-1 and tumor cell surface heparan sulfate (HS). The specific tumor cell surface HS oligosaccharide sequences that are necessary for binding to laminin-1 have not been characterized. To identify this laminin-binding oligosaccharide sequence, GlcNSO4-rich oligosaccharides terminating with [3H]2,5-anhydromannitol (AManR) residues were isolated from human breast cancer cell (MCF-7)-derived HS through hydrazinolysis/high pH (4.0) nitrous acid treatment/[3H]NaBH4 reduction. These oligosaccharides were chromatographed on a laminin-1 affinity column. A high affinity dodecasaccharide was isolated and characterized. Disaccharide analysis yielded IdoA(2-SO4) --> AManR(6-SO4) as the only disaccharide upon treatment of this dodecasaccharide with nitrous acid at low pH (1.5). The sequence of laminin-binding high affinity oligosaccharide is therefore [IdoA(2-SO4) --> GlcNSO4(6-SO4)]5[IdoA(2-SO4) --> AManR(6-SO4)]. Low affinity dodecasaccharides composed of [IdoA(2-SO4) --> GlcNSO4(6-SO4)]5, [IdoA(2-SO4) --> GlcNSO4] were also isolated by laminin-1 affinity chromatography. Molecular modeling studies indicate that a heparin-binding peptide sequence corresponding to amino acid residues 3010-3031 (KQNCLSSRASFRGCVRNLRLSR) in the G domain of laminin-1, modeled as a right-handed alpha-helix, carries an array of basic residues well placed to bind to clusters of sulfate groups on the high affinity dodecasaccharide.
Parthasarathy
N
N
Section of Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1040, USA. npartha@wfubmc.edu
Gotow
L F
LF
Bottoms
J D
JD
Kute
T E
TE
Wagner
W D
WD
Mulloy
B
B
D000595:Amino Acid Sequence; D000818:Animals; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004187:Disaccharides / Q000737:chemistry / Q000378:metabolism; D006497:Heparan Sulfate / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007797:Laminin / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D014407:Tumor Cells, Cultured
D004187:Disaccharides; D006497:Heparan Sulfate; D007797:Laminin; D010446:Peptide Fragments