title: X-ray reflectivity and grazing incidence diffraction studies of interaction between human adhesion/growth-regulatory galectin-1 and DPPE-GM1 lipid monolayer at an air/water interface.
abstract: The specific interaction of ganglioside GM1 with the homodimeric (prototype) endogenous lectin galectin-1 triggers growth regulation in tumor and activated effector T cells. This proven biorelevance directed interest to studying association of the lectin to a model surface, i.e. a 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine/ganglioside GM1 (80 : 20 mol%) monolayer, at a bioeffective concentration. Surface expansion by the lectin insertion was detected at a surface pressure of 20 mN/m. On combining the methods of grazing incidence X-ray diffraction and X-ray reflectivity, a transient decrease in lipid-ordered phase of the monolayer was observed. The measured electron density distribution indicated that galectin-1 is oriented with its long axis in the surface plane, ideal for cis-crosslinking. The data reveal a conspicuous difference to the way the pentameric lectin part of the cholera toxin, another GM1-specific lectin, is bound to the monolayer. They also encourage further efforts to monitor effects of structurally different members of the galectin family such as the functionally antagonistic chimera-type galectin-3.
authors.affiliation: Manuel Lujan Jr. Neutron Scattering Center, Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM, USA.
authors.forename: J
authors.initials: J
authors.lastname: Majewski
authors.forename: S
authors.initials: S
authors.lastname: André
authors.forename: E
authors.initials: E
authors.lastname: Jones
authors.forename: E
authors.initials: E
authors.lastname: Chi
authors.forename: H-J
authors.initials: HJ
authors.lastname: Gabius
mesh_terms: D002240:Carbohydrate Sequence; D002772:Cholera Toxin / Q000737:chemistry / Q000378:metabolism; D005677:G(M1) Ganglioside / Q000737:chemistry / Q000378:metabolism*; D037483:Galectin 1 / Q000378:metabolism; D037161:Galectins; D006801:Humans; D015994:Incidence; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: C430567:1,2-dihexadecanoyl-sn-glycero-3-phospho-(N-(4-nitrobenz)-2-oxa-1,3-diazolyl)ethanolamine; D037483:Galectin 1; D037161:Galectins; D008051:Lipid Bilayers; D010714:Phosphatidylethanolamines; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; D005677:G(M1) Ganglioside; D002772:Cholera Toxin