title: The shell organic matrix of the crossed lamellar queen conch shell (Strombus gigas).
abstract: In molluscs, the shell organic matrix comprises a large set of biomineral-occluded proteins, glycoproteins and polysaccharides that are secreted by the calcifying mantle epithelium, and are supposed to display several functions related to the synthesis of the shell. In the present paper, we have characterized biochemically the shell matrix associated to the crossed-lamellar structure of the giant queen conch Strombus gigas. The acid-soluble (ASM) and acid-insoluble (AIM) matrices represent an extremely minor fraction of the shell. Both are constituted of polydisperse and of few discrete proteins among which three fractions, obtained by preparative SDS-PAGE and named 1P3, 2P3 and 3P3, are dominant and were further characterized. Compared to other matrices, the acid-soluble matrix is weakly glycosylated (3%) and among the discrete components, only 3P3 seems noticeably glycosylated. The monosaccharide composition of the ASM shows that mannose represents the main monosaccharide. To our knowledge, this is the first report of a high ratio of this sugar in a skeletal matrix. Furthermore, the ASM interacts with the in vitro crystallization of calcium carbonate, but this interaction is moderate. It differs from that of the isolated 1P3 fraction but is similar to that of the 2P3 and 3P3 fractions. At last, antibodies developed from the 3P3 fraction were used to localize this fraction within the shell by immunogold. This study is the first one aiming at characterizing the organic matrix associated to the crossed-lamellar structure of the queen conch shell.
authors.affiliation: Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, Av. Fuentenueva, S/N, 18071 Granada, Spain; Departamento de Bioquímica y Parasitología Molecular, Facultad de Ciencias, Universidad de Granada, Av. Fuentenueva, S/N, 18071 Granada, Spain; UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France. Electronic address: tay@ugr.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Osuna-Mascaró
authors.affiliation: Departamento de Bioquímica y Parasitología Molecular, Facultad de Ciencias, Universidad de Granada, Av. Fuentenueva, S/N, 18071 Granada, Spain; UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France.
authors.forename: Teresa
authors.initials: T
authors.lastname: Cruz-Bustos
authors.affiliation: UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France.
authors.forename: Sana
authors.initials: S
authors.lastname: Benhamada
authors.affiliation: UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Guichard
authors.affiliation: UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France; UMR 7245 CNRS MCAM, MNHN, 12 Rue Buffon, 75005 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Marie
authors.affiliation: ICMUB, UMR CNRS 6302, Faculté des Sciences Mirande, Université de Bourgogne, 21000 Dijon, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Plasseraud
authors.affiliation: UPSP PROXISS, Département Agronomie Environnement, AgroSup Dijon, 26 Boulevard Docteur Petitjean, BP 87999, F-21079 Dijon Cedex, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Corneillat
authors.affiliation: UPSP PROXISS, Département Agronomie Environnement, AgroSup Dijon, 26 Boulevard Docteur Petitjean, BP 87999, F-21079 Dijon Cedex, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Alcaraz
authors.affiliation: Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, Av. Fuentenueva, S/N, 18071 Granada, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Checa
authors.affiliation: UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France. Electronic address: frederic.marin@u-bourgogne.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Marin
mesh_terms: D060105:Animal Shells / Q000737:chemistry* / Q000648:ultrastructure; D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry; D002241:Carbohydrates / Q000032:analysis; D003460:Crystallization; D049851:Gastropoda / Q000737:chemistry* / Q000648:ultrastructure; D006023:Glycoproteins / Q000032:analysis; D011506:Proteins / Q000032:analysis*
chemical_list: D002241:Carbohydrates; D006023:Glycoproteins; D011506:Proteins; D002119:Calcium Carbonate
keywords: Biomineralization; Calcifying matrix; Crossed-lamellar; Mollusc; Shell