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Query: UMLS:C0271276 (Hudson)
 1,066 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The noncollagenous domain of basement membrane collagen exists as a hexamer upon excision with bacterial collagenase. Two hexamer subtypes, differing in subunit composition, have been identified and several additional subtypes are possible because at least two, and possibly more, triple-helical molecules, differing in chain composition, exist in authentic basement membranes (Saus J, Wieslander J, Langeveld JPM, Quinones S, and Hudson BG. (1988) Identification of the Goodpasture antigen as the alpha 3(IV) chain of collagen IV. J. Biol. Chem. 263:13374-13380). In the present study, the physiochemical behavior of hexamer during two-dimensional electrophoresis was evaluated. The hexamers from three different membranes of bovine origin (lens capsule, glomerular, and placenta) were found to exhibit an unusual dissociative property during the pH gradient electrophoresis used in the first dimension; namely, the hexamers dissociate under nondenaturing conditions into monomer and dimer subunits concomitant with the resolution of subunits. This dissociative property provided the basis for a new procedure using chromatofocusing for the preparative resolution of hexamer subunits with retention of their native structure and capacity to associate into a hexamer configuration. Associative studies revealed that the capacity for hexamer assembly is contained within the monomer subunit, a property which may be of fundamental importance in the mechanism of the assembly of collagen IV protomers and the association of protomers forming a supramolecular structure.
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PMID:Unusual dissociative behavior of the noncollagenous domain (hexamer) of basement membrane collagen during electrophoresis and chromatofocusing. 237 21

The collagenase domain of bovine glomerular basement membrane was isolated in soluble form after limited digestion with pepsin. Gel filtration chromatography of the domain under denaturing conditions revealed that most of the polypeptide constituents exhibit apparent molecular weights greater than the type I collagen beta-chain, while approximately 15% are similar in size to that of alpha-chain. Carboxymethyl cellulose chromatography of the alpha-size region revealed that 70% of the protein was polypeptide XIV, as previously designated (West, T. W., Fox, J. W., Jodlowski, M., Freytag, J. W., and Hudson, B. G. (1980) J. Biol. Chem. 255, 10451-10459). This polypeptide exhibits an apparent molecular weight of 102,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An absolute molecular weight value of 86,000 was determined by sedimentation equilibrium ultracentrifugation in 6 M guanidine hydrochloride. About 15% of the mass is carbohydrate which exists in the form of glucosylgalactosylhydroxylysine. Thus, the polypeptide backbone has a molecular weight of 73,000, a value which is considerably smaller than the alpha-chains of classical collagen. The amino acid and carbohydrate composition and cyanogen bromide patterns indicate that polypeptide XIV has a structure similar to that of C-chain or alpha 1 (IV) collagen which has been identified in other tissues. In addition, the cyanogen bromide pattern of the entire collagenous domain is similar to that of polypeptide XIV, suggesting that the latter is a structural segment of many of the higher molecular weight components.
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PMID:Bovine glomerular basement membrane. Characterization of an alpha-size collagenous polypeptide. 725 9