title: Detection and quantitative analysis of two independent binding modes of a small ligand responsible for DC-SIGN clustering.
abstract: DC-SIGN (dendritic cell-specific ICAM-3 grabbing non-integrin) is a C-type lectin receptor (CLR) present, mainly in dendritic cells (DCs), as one of the major pattern recognition receptors (PRRs). This receptor has a relevant role in viral infection processes. Recent approaches aiming to block DC-SIGN have been presented as attractive anti-HIV strategies. DC-SIGN binds mannose or fucose-containing carbohydrates from viral proteins such as the HIV envelope glycoprotein gp120. We have previously demonstrated that multivalent dendrons bearing multiple copies of glycomimetic ligands were able to inhibit DC-SIGN-dependent HIV infection in cervical explant models. Optimization of glycomimetic ligands requires detailed characterization and analysis of their binding modes because they notably influence binding affinities. In a previous study we characterized the binding mode of DC-SIGN with ligand 1, which shows a single binding mode as demonstrated by NMR and X-ray crystallography. In this work we report the binding studies of DC-SIGN with pseudotrisaccharide 2, which has a larger affinity. Their binding was analysed by TR-NOESY and STD NMR experiments, combined with the CORCEMA-ST protocol and molecular modelling. These studies demonstrate that in solution the complex cannot be explained by a single binding mode. We describe the ensemble of ligand bound modes that best fit the experimental data and explain the higher inhibition values found for ligand 2.
authors.affiliation: Glycosystems Laboratory. Instituto de Investigaciones Químicas (IIQ)/cicCartuja. CSIC/US, Americo Vespucio, 49, 41092 Sevilla, Spain. pedro.nieto@iiq.csic.es.
authors.forename: C
authors.initials: C
authors.lastname: Guzzi
authors.forename: P
authors.initials: P
authors.lastname: Alfarano
authors.forename: I
authors.initials: I
authors.lastname: Sutkeviciute
authors.forename: S
authors.initials: S
authors.lastname: Sattin
authors.forename: R
authors.initials: R
authors.lastname: Ribeiro-Viana
authors.forename: F
authors.initials: F
authors.lastname: Fieschi
authors.forename: A
authors.initials: A
authors.lastname: Bernardi
authors.forename: J
authors.initials: J
authors.lastname: Weiser
authors.forename: J
authors.initials: J
authors.lastname: Rojo
authors.forename: J
authors.initials: J
authors.lastname: Angulo
authors.forename: P M
authors.initials: PM
authors.lastname: Nieto
mesh_terms: D001665:Binding Sites / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D003713:Dendritic Cells; D006801:Humans; D037181:Lectins, C-Type / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D014312:Trisaccharides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D008024:Ligands; D011956:Receptors, Cell Surface; D014312:Trisaccharides; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin