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Biomedical subjects

E J Miller

Publications and source records attributed to E J Miller.

At least 145 records · Page 8Linked to original sources
PubMed1977

The covalent structure of cartilage collagen. Evidence for sequence heterogeneity of bovine alpha1(II) chains.

During studies on the amino acid sequence of bovine nasal cartilage collagen, the cyanogen bromide peptide alpha1(II)-CB11 was degraded to smaller peptides with trypsin. One of the tryptic peptides, T5, which contained 39 residues was shown by amino acid and sequence analyses to occur in a predominant form that contained glutamine at position 5 and in a second form with leucine at this site. In addition to the heterogeneity at this position, amino acid analyses of five different preparations revealed that the peptide with leucine contained a seryl residue not found in the major form. Sequence heterogeneity at a third position of alpha1(II) was demonstrated by the isolation of a hexapeptide (T2) from the trypsin digest of alpha1(II)-CB11 which contained 0.21 residue of alanine and 0.77 of leucine. Both the leucine and alanine of T2 were removed after the second cycle of subtractive Edman degradation. These data show that at least two types of alpha1(II) chains, designated as alpha1(II)Major and alpha1(II)Minor, exist in bovine nasal cartilage. Further considerations suggest that these two chains are probably not variants derived from allelic genes but are the products of separate genes.

Amino Acid Sequence↗
PubMed1977

Transitions in collagen types during matrix-induced cartilage, bone, and bone marrow formation.

The localization of types I, II, and III collagens during bone matrix-induced sequential differentiation of cartilage, bone, and bone marrow was studied by specific immunofluorescence. Subcutaneous transplantation of coarse powders of demineralized rat bone matrix into allogeneic recipients resulted in new bone formation. After a transient appearance of polymorphonuclear leukocytes in the implant, fibroblasts appeared in close continguity to the matrix on day 3. Type III collagen was then localized as a fine network around the invading fibroblasts. On days 4--6 smaller amounts of type I were also detected around these proliferating cells. With the onset of chondrogenesis, type II collagen was detected in the cartilage matrix on day 6 and persisted until the early stages of bone formation. Vascular invasion of the implant was accompanied by osteogenesis on day 10. Type I collagen was demonstrated in the newly deposited bone matrix coating the surfaces of cartilage spicules and particles of implanted bone powder. On day 17 and thereafter, type III collagen was localized as a fibrous array around nests of hematopoietic cells.

Animals↗
PubMed1976

Biochemical characteristics and biological significance of the genetically-distinct collagens.

In recent years it has become evident that genetic polymorphism is dramatically expressed in the structural protein, collagen. Current information on the biochemical properties, biosynthesis, and tissue distribution of Type I, II, and III collagens is summarized with special reference to possible unique functional roles fulfilled by each of these collagens.

Amino Acid Sequence↗
PubMed1976

Studies on the sulfhydryl groups in type III collagen.

The Type III collagen molecule, [alpha](III)]3, is comprised of three alphal(III) chains each of which contains two cysteinyl residues. Free sulfhydryl groups, however, could not be detected in the denatured, trimeric gamma-component of Type III collagen as judged by the failure to form derivatives with the alkylating reagents iodo-[14C]acetic acid and 4-vinylpyridine. This absence of sulfhydryl group reactivity did not appear to result from disulfide-binding between Type III collagen and noncollagenous peptides. Collectively, the results indicate that all of the six sulfhydryl groups of the Type III collagen molecule participate in interchain disulfide-bonding.

Amino Acids↗
PubMed1976

The covalent structure of cartilage collagen. Amino acid sequence of the NH2-terminal helical portion of the alpha 1 (II) chain.

The amino acid sequence of 162 residues from the NH2-terminal region of bovine alpha 1 (II) is reported. Automated sequence analysis of chains from pepsin-treated type II collagen indicated the sequence and order of two CNBr peptides, alpha 1 (II)-CB2 and alpha 1 (II)-CB3, at the beginning of the repetitive triplet sequence of alpha 1 (II). The sequences of alpha 1 (II)-CB6, alpha 1 (II),-CB12, and 39 residues of alpha 1 (II)-CB11 were determined largely by automated Edman degradation. Comparative sequence data are reported which indicate that the level of homology between alpha 1 (I) and alpha 1 (II) chains in the NH2-terminal region is about 80%. A similar level of homology was reported for the central portions of these chains (Butler, W.T., Miller, E.J., Finch, J.E., Jr., and Inagami, T. (1974), Biochem. Biophys. Res. Commun. 57 190). The degree of intraspecies variability between chain types is thus greater than the interspecies variability for a single chain type. Within the sequence reported here, the alpha 1 (II) chain contains glucosylgalactosylhydroxylysine at three positions. The corresponding sequence of alpha 1 (I) contains only one clycosylated hydroxylysine with the other two positions occupied by lysyl residues.

Amines↗
PubMed1976

Cleavage of Type II and III collagens with mammalian collagenase: site of cleavage and primary structure at the NH2-terminal portion of the smaller fragment released from both collagens.

Collagenase cleavage of human Type II and III collagens has been studied using a highly purified preparation of rabbit tumor collagenase. Progress of the reactions in solution was followed by viscometry and the results indicated that under the conditions employed Type III collagen molecules were cleaved at approximately five times the rate of Type II molecules. Cleavage products of the reactions were isolated in denatured form by agarose molecular sieve chromatography. The molecular weights and amino acid compositions of the products demonstrated that Type II and III molecules had been cleaved at the characteristic three-quarter, one-quarter locus, giving rise to a large fragment derived from the NH2-terminal portion of the molecule and a smaller fragment representing the COOH-terminal region. The amino acid sequence at the NH2-terminal portion of the smaller fragment derived from Type II collagen was determined to be Ile-Ala-Gly-Gln-Arg, and the corresponding region from Type III collagen was found to have the sequence Leu-Ala Gly-Leu-Arg. These sequences for alpha1(II) and alpha1(III) chains adjacent to the site of collagenase cleavage along with previous data for alpha1(I) and alpha2 chains indicate that the minimum specific sequence required for collagenase cleavage is Gly-Ile-Ala or Gly-Leu-Ala. Inspection of the available sequence data for collagen alpha chains indicates that the latter sequences are found in at least three additional locations at which collagenase cleavage does not occur. Each of the sequences which are apparently not substrates for collagenase, however, are followed by a Gly-X-Hyp sequence. We suggest, then, that a minimum of five residues in collagen alpha chains COOH-terminal to the cleavage site comprise the substrate recognition site.

Amino Acid Sequence↗
PubMed1976

Changes in type of collagen synthesized as clones of chick chondrocytes grow and eventually lose division capacity.

Clones of embryonic chick chondrocytes have been isolated and collagen biosynthesis has been followed as the clones grow and eventually lose division capacity. Analysis of collagen type at each successive subculture until the time of cellular senescence has shown that a change in synthesis occurs from the cartilage-specific Type II collagen (chain composition [alpha1(II)]3) to a mixture of Type I collagen (chain composition [alpha1(I)2alpha2) and the Type I trimer (chain composition[alpha1(I)]3). The results demonstrate unequivocally that the expression of the chick chondrocyte phenotype is unstable in vitro, and that previous experiments with mass cultures of chondrocytes cannot be accounted for by overgrowth of fibroblasts. Since similar morphological changes and a similar "switching" in collagen biosynthesis have been observed after growth of chondrocytes for a few days in 5-bromo-2'-deoxyuridine, it is proposed that growth in this analog accelerates those changes that eventually lead to cellular senescence.

Aging↗
PubMed1976

Visualization of type I and II collagens in tissue sections by immunohistologic techniques.

Rabbit and rat antibodies were prepared against Type I and II collagens derived from bovine skin and articular cartilage, respectively. As judged by passive hemagglutination and radioimmune assays, these antibodies could be rendered generally specific for the type of collagen used for immunization by immunoadsorption. Thus, antibodies to Type II collagen did not cross-react with Type I and III collagens from skin. However, antibodies to Type I collagen still showed some cross-reaction with Type III collagen. Antibodies to Type I procollagen showed a negligible degree of cross-reaction with Type III procollagen. These purified antibodies reacted strongly with bovine and human tissue collagen as demonstrated by indirect immunoflourescence. Antibodies to Type I collagen stained dermal tissue, perichondral tissue, kidney stroma, aortic tissue, and annulus fibrosus. Antibodies to Type II collagen stained mainly the hyaline matrix of rib cartilage and nucleus pulposus. The staining patterns with anti-Type I procollagen were similar but not identical to that found with antibodies to Type I collagen. Neither of these antibodies reacted with kidney glomerular basement membrane. These antibody reagents are recommended as a sensitive and rapid screening tool for studying tissue distribution of collagen under normal and pathologic conditions.

Animals↗