Structure and composition of type IV collagen of bovine aorta.
To determine the chain composition of type IV collagen of bovine thoracic aorta, we analyzed collagenase-solubilized carboxyl-terminal noncollagenous (NC1)-domains by high-pressure liquid chromatography, two-dimensional electrophoresis, immunoblotting and enzyme-linked immunoassay. In addition to the classical alpha 1- and alpha 2-chains, we found small amounts of the recently discovered alpha 3-, alpha 4- and alpha 5-chains. The alpha 3- and alpha 4-chains were, collectively, 7-13% of the total, and the alpha 5-chain was present in a low amount. Seventy-nine percent of the NC1-domains were dimerized. Immunolocalization studies on sections of aorta showed that the alpha 3- and alpha 5-chains were present, along with alpha 1- and alpha 2-chains, in the subendothelium and media. In capillaries of the media, the alpha 3-chain was found at relatively high levels and was co-localized with alpha 1- and alpha 2-chains. Digestion of aorta with Pseudomonas aeruginosa elastase yielded soluble multimolecular assemblies of type IV collagen. Electron microscopy results provided a direct demonstration of the supramolecular structure, in which the collagen molecules were tetramerized at the amino-terminal end and dimerized at the carboxyl-terminal end.
Reddy
G K
GK
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421.
Gunwar
S
S
Kalluri
R
R
Hudson
B G
BG
Noelken
M E
ME
D000818:Animals; D001011:Aorta / Q000737:chemistry*; D001485:Basement Membrane / Q000737:chemistry; D001665:Binding Sites; D002417:Cattle; D003094:Collagen / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D010196:Pancreatic Elastase
D003094:Collagen; D010196:Pancreatic Elastase