title: Structural characterization of TSC-36/Flik: analysis of two charge isoforms.
abstract: Recombinant forms of the glycoprotein TSC-36/Flik were expressed in human cells and used to compare their structural and functional properties with those described for other members of the BM-40/SPARC/osteonectin protein family. TSC-36 was found to occur in two charge isoforms that differ in the extent of sialylation of otherwise identical N-linked, complex type oligosaccharides. Conformational analysis with both circular dichroism and intrinsic fluorescence spectroscopy showed a lack of significant structural changes upon calcium addition or depletion. This finding is in contrast to results obtained for several other BM-40 family members and indicates that the extracellular calcium-binding domain in TSC-36 is non-functional. The lack of conservation of important functional features common to several other members of the BM-40 family indicates that TSC-36, despite its sequence homology to BM-40, has evolved clearly distinct properties.
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, D-50931 Cologne, Germany.
authors.forename: Harald O
authors.initials: HO
authors.lastname: Hambrock
authors.forename: Brigitte
authors.initials: B
authors.lastname: Kaufmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Müller
authors.forename: Franz-Georg
authors.initials: FG
authors.lastname: Hanisch
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Nose
authors.forename: Mats
authors.initials: M
authors.lastname: Paulsson
authors.forename: Patrik
authors.initials: P
authors.lastname: Maurer
authors.forename: Ursula
authors.initials: U
authors.lastname: Hartmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D038702:Follistatin-Related Proteins / Q000737:chemistry* / Q000235:genetics; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013050:Spectrometry, Fluorescence
chemical_list: D017931:DNA Primers; D038702:Follistatin-Related Proteins; C448720:Fstl1 protein, mouse; D020033:Protein Isoforms; D011994:Recombinant Proteins