title: Impact of sulfation pattern on the conformation and dynamics of sulfated fucan oligosaccharides as revealed by NMR and MD.
abstract: Sulfated fucans from sea urchin egg jelly express well-defined chemical structures that vary with species. This species specificity regulates the sperm acrosome reaction, a critical step to assure intra-specific fertilization. In addition, these polysaccharides are involved in other biological activities such as anticoagulation. Although sulfation patterns are relevant to the levels of response in both activities, conformation and dynamics of these glycans are also contributing factors. However, data about these features of sulfated fucans are very rare. To address this, we have employed nuclear magnetic resonance experiments combined with molecular dynamics on structurally defined oligosaccharides derived from two sulfated fucans. The results have indicated that the oligosaccharides are flexible in solution. Ring conformation of their composing units displays just the (1)C4 chair configuration. In a particular octasaccharide, composed of two tetrasaccharide sequences, inter-residual hydrogen bonds play a role to decrease dynamics in these repeating units. Conversely, the linking disaccharide [-3)-α-L-Fucp-2(OSO3(-))-(1-3)-α-L-Fucp-4(OCO3(-))-(1-] located right between the two tetrasaccharide units has amplified motions suggested to be promoted by electrostatic repulsion of sulfates on opposite sides of the central glycosidic bond. This conjunction of information about conformation and dynamics of sulfated fucan oligosaccharides provides new insights to explain how these glycans behave free in solution and influenced by sulfation patterns. It may also serve for future studies concerning structure-function relationship of sulfated fucans, especially those involving sea urchin fertilization and anticoagulation.
authors.affiliation: Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil.
authors.forename: Ismael N L
authors.initials: IN
authors.lastname: Queiroz
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.
authors.forename: Xiaocong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.
authors.forename: John N
authors.initials: JN
authors.lastname: Glushka
authors.affiliation: Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil.
authors.forename: Gustavo R C
authors.initials: GR
authors.lastname: Santos
authors.affiliation: Centro Nacional de Ressonância Nuclear Magnética de Macromoléculas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brasil.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Valente
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.
authors.forename: James H
authors.initials: JH
authors.lastname: Prestegard
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Woods
authors.affiliation: Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil.
authors.forename: Paulo A S
authors.initials: PA
authors.lastname: Mourão
authors.affiliation: Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil pominvh@bioqmed.ufrj.br vhpomin@gmail.com.
authors.forename: Vitor H
authors.initials: VH
authors.lastname: Pomin
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D056004:Molecular Dynamics Simulation; D011134:Polysaccharides / Q000737:chemistry*; D012617:Sea Urchins
chemical_list: D011134:Polysaccharides; C007789:fucoidan
keywords: MD; NMR; NOE; conformation; oligosaccharides; spin relaxation; sulfated fucan