Non-Uniform Triple Helical Structure in Chick Skin Type I Collagen on Thermal Denaturation: Raman Spectroscopic Study

1998 ◽  
Vol 53 (5-6) ◽  
pp. 383-388 ◽  
Author(s):  
V. Renugopalakrishnan ◽  
L. A. Carreira ◽  
T. W. Collette ◽  
J. C. Dobbs ◽  
G. Chandraksasan ◽  
...  

The individual chains in the triple helix of collagen occur in a conformation related to polyproline II because of the presence of large number of imino peptide bonds. However, these residues are not evenly distributed in the collagen molecule which also contains many non-imino residues. These non-imino regions of collagen may be expected to show preference for other than triple helical conformations. The appearance of several Raman bands in solution phase at 65 °C raises the possibility of non-uniform triple helical structure in collagen. Raman spectroscopic studies on collagen in the solid state and in solution at a temperature greater than its denaturation temperature, reported here suggest that denatured collagen may exhibit an ensemble of conformational states with yet unknown implications to the biochemical interactions of this important protein component of connective tissues.

Glycobiology ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 830-843
Author(s):  
Ming Tang ◽  
Xiaocong Wang ◽  
Neha S Gandhi ◽  
Bethany Lachele Foley ◽  
Kevin Burrage ◽  
...  

Abstract Collagen undergoes many types of post-translational modifications (PTMs), including intracellular modifications and extracellular modifications. Among these PTMs, glycosylation of hydroxylysine (Hyl) is the most complicated. Experimental studies demonstrated that this PTM ceases once the collagen triple helix is formed and that Hyl-O-glycosylation modulates collagen fibrillogenesis. However, the underlying atomic-level mechanisms of these phenomena remain unclear. In this study, we first adapted the force field parameters for O-linkages between Hyl and carbohydrates and then investigated the influence of Hyl-O-glycosylation on the structure of type I collagen molecule, by performing comprehensive molecular dynamic simulations in explicit solvent of collagen molecule segment with and without the glycosylation of Hyl. Data analysis demonstrated that (i) collagen triple helices remain in a triple-helical structure upon glycosylation of Hyl; (ii) glycosylation of Hyl modulates the peptide backbone conformation and their solvation environment in the vicinity and (iii) the attached sugars are arranged such that their hydrophilic faces are well exposed to the solvent, while their hydrophobic faces point towards the hydrophobic portions of collagen. The adapted force field parameters for O-linkages between Hyl and carbohydrates will aid future computational studies on proteins with Hyl-O-glycosylation. In addition, this work, for the first time, presents the detailed effect of Hyl-O-glycosylation on the structure of human type I collagen at the atomic level, which may provide insights into the design and manufacture of collagenous biomaterials and the development of biomedical therapies for collagen-related diseases.


2013 ◽  
Vol 54 ◽  
pp. 155-159 ◽  
Author(s):  
Ganesh Shanmugam ◽  
Samala Murali Mohan Reddy ◽  
Venkatachalam Natarajan ◽  
Balaraman Madhan

2015 ◽  
Vol 293 (9) ◽  
pp. 2655-2662 ◽  
Author(s):  
Meenatchi Sundaram Saravanan ◽  
Jayaraman Jayamani ◽  
Ganesh Shanmugam ◽  
Balaraman Madhan

1990 ◽  
Vol 95 (4) ◽  
pp. 649-657 ◽  
Author(s):  
D.E. Birk ◽  
J.M. Fitch ◽  
J.P. Babiarz ◽  
K.J. Doane ◽  
T.F. Linsenmayer

The small-diameter fibrils of the chick corneal stroma are heterotypic, composed of both collagen types I and V. This tissue has a high concentration of type V collagen relative to other type I-containing tissues with larger-diameter fibrils, suggesting that heterotypic interactions may have a regulatory role in the control of fibril diameter. The interactions of collagen types I and V were studied using an in vitro self-assembly system. Collagens were purified from lathyritic chick embryos in the presence of protease inhibitors. The type V collagen preparations contained higher molecular weight forms of the alpha 1(V) and alpha 2(V) chains constituting 60–70% of the total. Rotary-shadow electron micrographs showed a persistence of a small, pepsin-sensitive terminal region in an amount consistent with that seen by electrophoresis. In vitro, this purified type V collagen formed thin fibrils with no apparent periodicity, while type I collagen fibrils had a broad distribution of large diameters. However, when type I collagen was mixed with increasing amounts of type V collagen a progressive and significant decrease in both the mean fibril diameter and the variance was observed for D periodic fibrils. The amino-terminal domain of the type V collagen molecule was required for this regulatory effect and in its absence little diameter reducing activity was observed. Electron microscopy using collagen type-specific monoclonal antibodies demonstrated that the fibrils formed were heterotypic, containing both collagen types I and V. These data indicate that the interaction of type V with type I collagen is one mechanism modulating fibril diameter and is at least partially responsible for the regulation of collagen fibril formation.


1993 ◽  
Vol 39 (4) ◽  
pp. 635-640 ◽  
Author(s):  
J Risteli ◽  
I Elomaa ◽  
S Niemi ◽  
A Novamo ◽  
L Risteli

Abstract We developed a radioimmunoassay (RIA) for the carboxy-terminal telopeptides of type I collagen (ICTP), cross-linked with the helical domain of another type I collagen molecule, after isolation from human femoral bone. The cross-linked peptide was liberated by digesting insoluble, denatured bone collagen either with bacterial collagenase or with trypsin, and purified by two successive reversed-phase separations on HPLC, with monitoring of pyridinoline-specific fluorescence. The purity of the peptide was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its origin in the type I collagen fibers was determined by amino-terminal amino acid sequencing. Polyclonal antibodies and a separation reagent containing second antibody and polyethylene glycol are used in the RIA. An immunologically identical, somewhat larger antigen is present in human serum; its concentration increases in multiple myeloma and in rheumatoid arthritis. The ICTP antigen seems to be cleared from the circulation by the kidneys, because glomerular filtration rates that are two-thirds of normal or less are associated with increased circulating ICTP concentrations. The CVs of the method are between 3% and 8% for a wide range of concentrations. The analysis of 40 serum samples can be completed in 4 h.


1984 ◽  
Vol 217 (1) ◽  
pp. 103-115 ◽  
Author(s):  
J F Bateman ◽  
T Mascara ◽  
D Chan ◽  
W G Cole

Cultured skin fibroblasts from seven consecutive cases of lethal perinatal osteogenesis imperfecta (OI) expressed defects of type I collagen metabolism. The secretion of [14C]proline-labelled collagen by the OI cells was specifically reduced (51-79% of control), and collagen degradation was increased to twice that of control cells in five cases and increased by approx. 30% in the other two cases. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed that four of the OI cell lines produced two forms of type I collagen consisting of both normally and slowly migrating forms of the alpha 1(I)- and alpha 2(I)-chains. In the other three OI cell lines only the ‘slow’ alpha (I)′- and alpha 2(I)′-chains were detected. In both groups inhibition of the post-translational modifications of proline and lysine resulted in the production of a single species of type I collagen with normal electrophoretic migration. Proline hydroxylation was normal, but the hydroxylysine contents of alpha 1(I)′- and alpha 2(I)′-chains purified by h.p.l.c. were greater than in control alpha-chains. The glucosylgalactosylhydroxylysine content was increased approx. 3-fold while the galactosylhydroxylysine content was only slightly increased in the alpha 1(I)′-chains relative to control alpha 1(I)-chains. Peptide mapping of the CNBr-cleavage peptides provided evidence that the increased post-translational modifications were distributed throughout the alpha 1(I)′- and alpha 2(I)′-chains. It is postulated that the greater modification of these chains was due to structural defects of the alpha-chains leading to delayed helix formation. The abnormal charge heterogeneity observed in the alpha 1 CB8 peptide of one patient may reflect such a structural defect in the type I collagen molecule.


1972 ◽  
Vol 45 (1) ◽  
pp. 173-181 ◽  
Author(s):  
M. M. Coleman ◽  
J. R. Shelton ◽  
J. L. Koenig

Abstract The shoulder observed at approximately 440 cm−1 in Raman spectra of CB vulcanizates prepared from MBT based vulcanizing systems has been shown to consist of two components. There are Raman lines contributing at 440 cm−1 and 424 cm−1. The former is due to ZnO present as an extra-network material while the latter appears to be associated with polysulfidic structures. The Raman line at 505 cm−1 seen in extracted vulcanizates prepared from CB-MBT-Sulfur-ZnO-Lauric acid recipes does not appear to be solely due to disulfidic structures. The major contribution appears to be associated with an unsaturated cyclic sulfide and is most probably due to a structure of the type (I). If the assignment to cyclic sulfidic structures such as (I) is confirmed, it will have major significance with regard to the mechanism of accelerated sulfur vulcanization.


1983 ◽  
Vol 61 (9) ◽  
pp. 1012-1017 ◽  
Author(s):  
James R. A. Leushner

Collagens were obtained from decalcified human embryonic calvaria by pepsin digestion. After removal of the type I collagen, the more soluble collagens were precipitated at 1.2 M NaCl (acid pH), followed by a selective precipitation step at neutral pH, using a NaCl concentration of 4.5 M. Analysis of this latter precipitate by polyacrylamide slab gel electrophoresis and ion-exchange chromatography revealed the presence of a heterogeneous group of proteins ranging in size from approximately 10 000 daltons to over 120 000 daltons. Proteolysis, as a source for these diverse components, was ruled out both by studies employing protease inhibitors and experiments employing thrombin which indicated that no helical denaturation had occurred during extraction. A comparison with standard collagen preparations suggested that the major bands present in these samples corresponded to the α1-, α2-, and α3- chains of type V collagen. The data also showed that the major helical organization of these chains was [α1(V)]2 α2(V). Data suggesting that proteolysis can occur during the chromatographic separation of the individual α-chains are presented. This proteolysis was sensitive to inhibitors and its possible role in modifying the chain composition of type from calvaria and other tissues is discussed. Unique cyanogen bromide peptides distinguishable from those of type I and type V were present in these precipitates and suggests the presence of novel collagen types. The small amounts of these collagens precluded a determination of the exact nature of these components.


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