title: Structure of fucoidan from brown seaweed Turbinaria ornata as studied by electrospray ionization mass spectrometry (ESIMS) and small angle X-ray scattering (SAXS) techniques.
abstract: The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.
authors.affiliation: Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau giay, Hanoi, Vietnam. thuyttt@ich.vast.ac.vn
authors.forename: Thuy Thi Thu
authors.initials: TT
authors.lastname: Thanh
authors.forename: Van Thi Thanh
authors.initials: VT
authors.lastname: Tran
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yuguchi
authors.forename: Ly Minh
authors.initials: LM
authors.lastname: Bui
authors.forename: Tai Tien
authors.initials: TT
authors.lastname: Nguyen
mesh_terms: D005643:Fucose / Q000737:chemistry; D005690:Galactose / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D053838:Scattering, Small Angle; D012624:Seaweed / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013431:Sulfates / Q000737:chemistry; D014965:X-Rays
chemical_list: D011134:Polysaccharides; D013431:Sulfates; D005643:Fucose; C007789:fucoidan; D005690:Galactose