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Biomedical subjects

H Wiedemann

Publications and source records attributed to H Wiedemann.

66 records · Page 4Linked to original sources
PubMed1975

Comparative electron-microscope studies on type-III and type-I collagens.

Long-spacing-segment crystallites prepared from type III collagen with the chain composition [alpha1(III)]3 and type I collagen with the chain composition [alpha(I)]i12alpha2 have been compared in the electron microscope after positive. staining with phosphotungstic acid and uranyl acetate. The comparison revealed several differences in intensities of the cross-striation bands as well as significant differences in band positions. The latter occur most prominently in three distinct regions of the crystallites. Further, crystallites prepared from type III collagen contain an additional intensely staining band in an area corresponding to the carboxy-terminal end of the molecule. The latter band is still observed following limited pepsin digestion and presumably represents a slight elongation of the helical portion of the type III molecule when compared to the type I molecule. In spite of the somewhat altered distribution of charged groups as indicated in studies on the long-spacing-segment crystallites, type III molecules are capable of forming fibrils of the native type with a cross-striation pattern and periodicity virtually identical to that observed when type I molecules are precipitated as native fibers.

Amino Acid Sequence↗
PubMed1975

Isolation, chemical and electron microscopical characterization of neutral-salt-soluble type III collagen and procollagen from fetal bovine skin.

Extraction of fetal bovine skin at neutral pH and in the presence of protease inhibitors solubilized substantial amounts of type I and type type III collagen and Type III procollagen. Type I and Type III collagen were separated from each other by salt precipitation, and DEAE-cellulose chromatography was used to separate collagen from procollagen. The main chain constituents in type III collagen and procollagen were disulfide-bonded gamma and pgamma components, respectively. Amino acid composition, cross striation banding as observed using electron microscopy, cyanogen bromide peptide patterns in disc electrophoresis gels and resistance of the disulfide regions to pepsin digestion indicated a close similarity to previously described insoluble type III collagen, which was solubilized by limited pepsin digestion. Electron microscopy of long-spacing-segment crystallites and evidence for an extended form of the disulfide-bonded cyanogen bromide peptide suggested that neutral-salt-soluble type III collagon is longer at its C-terminal end by about 10 to 20 amino acid residues than pepsin-treated material. A small elongation was also indicated in the N-terminal portion of the molecule. Procollagen has an additional N-terminal extension with a length of about 160 A, but no difference was observed between collagen and procollagen at their C-terminal ends.

Amino Acids↗