Effects of ultraviolet radiation on the type-I collagen protein triple helical structure: A method for measuring structural changes through optical activity

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.

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Osteogenesis imperfecta type IV: evidence of abnormal triple helical structure of type I collagen

Human Genetics ◽

10.1007/bf00278784 ◽

1986 ◽

Vol 74 (1) ◽

Cited By ~ 16

Author(s):

R.J. Wenstrup ◽

A.G.W. Hunter ◽

P.H. Byers

Keyword(s):

Osteogenesis Imperfecta ◽

Type I Collagen ◽

Helical Structure ◽

Type I ◽

Osteogenesis Imperfecta Type ◽

Type Iv ◽

Triple Helical Structure

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High concentration of propanol does not significantly alter the triple helical structure of type I collagen

Colloid & Polymer Science ◽

10.1007/s00396-015-3670-0 ◽

2015 ◽

Vol 293 (9) ◽

pp. 2655-2662 ◽

Cited By ~ 5

Author(s):

Meenatchi Sundaram Saravanan ◽

Jayaraman Jayamani ◽

Ganesh Shanmugam ◽

Balaraman Madhan

Keyword(s):

Type I Collagen ◽

Helical Structure ◽

Type I ◽

High Concentration ◽

Triple Helical Structure

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Transcriptomics Study to Determine the Molecular Mechanism by which sIL-13Rα2-Fc Inhibits Caudal Intervertebral Disc Degeneration in Rats

BioMed Research International ◽

10.1155/2020/7645989 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Xin Wang ◽

Jianshi Tan ◽

Junhao Sun ◽

Pengzhong Fang ◽

Jinlei Chen ◽

...

Keyword(s):

Intervertebral Disc ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Type I Collagen ◽

Type Ii Collagen ◽

Type I ◽

Model Group ◽

Expression Levels ◽

Protein Levels ◽

Collagen Protein

Background. Intervertebral disc degeneration is related to tissue fibrosis. ADAMTS can degrade the important components of the ECM during the process of intervertebral disc degeneration, ultimately resulting in the loss of intervertebral disc function. sIL-13Rα2-Fc can inhibit fibrosis and slow down the degeneration process, but the mechanism involved remains unclear. Objective. To determine the mechanism by which sIL-13Rα2-Fc inhibits ECM degradation and reduces intervertebral disc tissue fibrosis using a transcriptomics analysis. Methods. A rat model of caudal intervertebral disc degeneration was established, and Sirius red staining was used to observe the pathological changes in the caudal intervertebral disc. Transcriptome sequencing was employed to assess the gene expression profiles of the intervertebral disc tissues in the model group and the sIL-13Rα2-Fc-treated group. Differentially expressed genes were identified and analyzed using GO annotation and KEGG pathway analyses. Real-time fluorescence quantitative PCR was used to verify the expression levels of candidate genes. The levels of GAG and HA were quantitatively assessed by ELISA, and the levels of collagen I and collagen II were analyzed by western blotting. Results. Sirius red staining showed that in the model group, the annulus fibrosus was disordered, the number of breaks increased, and the type I collagen protein levels increased, whereas in the sIL-13Rα2-Fc group, the annulus fibrosus was ordered, the number of breaks decreased, and the type II collagen protein levels increased. In comparison with the model group, we identified 58 differentially expressed genes in the sIL-13Rα2-Fc group, and these were involved in 35 signaling pathways. Compared with those in the model group, the mRNA expression levels of Rnux1, Sod2, and Tnfaip6 in the IL-13Rα2-Fc group were upregulated, and the mRNA expression levels of Aldh3a1, Galnt3, Fgf1, Celsr1, and Adamts8 were downregulated; these results were verified by real-time fluorescence quantitative PCR. TIMP-1 (an ADAMTS inhibitor) and TIMP-1 combined with the sIL-13Rα2-Fc intervention increased the levels of GAG and HA, inhibited the expression of type I collagen, and promoted the expression of type II collagen. Conclusion. Adamts8 may participate in the degradation of ECM components such as GAG and HA and lead to an imbalance in the ECM of the intervertebral disc, resulting in intervertebral disc degeneration. sIL-13Rα2-Fc promoted anabolism of the ECM and increased the levels of ECM components by inhibiting the expression of Adamts8, thus maintaining the dynamic equilibrium of the ECM and ultimately delaying intervertebral disc degeneration.

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Mechanical stretch modulates TGF-β1 and α1(I) collagen expression in fetal human intestinal smooth muscle cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1999.277.5.g1074 ◽

1999 ◽

Vol 277 (5) ◽

pp. G1074-G1080 ◽

Cited By ~ 14

Author(s):

Jorge A. Gutierrez ◽

Hilary A. Perr

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Type I Collagen ◽

Intestinal Smooth Muscle ◽

Type I ◽

Collagen Mrna ◽

Collagen Expression ◽

Collagen Protein ◽

Mrna Content ◽

Tgf Β1

Intestinal muscle undergoes stretch intermittently during peristalsis and persistently proximal to obstruction. The influence of this pervasive biomechanical force on developing smooth muscle cell function remains unknown. We adapted a novel in vitro system to study whether stretch modulates transforming growth factor-β1 (TGF-β1) and type I collagen protein and component α1 chain [α1(I) collagen] expression in fetal human intestinal smooth muscle cells. Primary confluent cells at 20-wk gestation, cultured on flexible silicone membranes, were subjected to two brief stretches or to 18 h tonic stretch. Nonstretched cultures served as controls. TGF-β1 protein was measured by ELISA and type I collagen protein was assayed by Western blot. TGF-β1 and α1(I) collagen mRNA abundance was determined by Northern blot analysis, quantitated by phosphorimaging, and normalized to 18S rRNA. Transcription was examined by nuclear run-on assay. Tonic stretch increased TGF-β1 protein 40%, type I collagen protein 100%, TGF-β1 mRNA content 2.16-fold, and α1(I) collagen mRNA 3.80-fold and enhanced transcription of TGF-β1 and α1(I) collagen by 3.1- and 4.25-fold, respectively. Brief stretch stimulated a 50% increase in TGF-β1 mRNA content but no change in α1(I) collagen. Neutralizing anti-TGF-β1 ablated stretch-mediated effects on α1(I) collagen. Therefore, stretch upregulates transcription for TGF-β1, which stimulates α1(I) collagen gene expression in smooth muscle from developing gut.

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Effect of hydroxylysine-O-glycosylation on the structure of type I collagen molecule: A computational study

Glycobiology ◽

10.1093/glycob/cwaa026 ◽

2020 ◽

Vol 30 (10) ◽

pp. 830-843

Author(s):

Ming Tang ◽

Xiaocong Wang ◽

Neha S Gandhi ◽

Bethany Lachele Foley ◽

Kevin Burrage ◽

...

Keyword(s):

Force Field ◽

Type I Collagen ◽

Computational Study ◽

Experimental Studies ◽

Helical Structure ◽

Atomic Level ◽

Collagen Molecule ◽

Type I ◽

Dynamic Simulations ◽

Force Field Parameters

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.

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Role of matrix metalloprotease-9 in hyperoxic injury in developing lung

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00441.2007 ◽

2008 ◽

Vol 295 (4) ◽

pp. L584-L592 ◽

Cited By ~ 45

Author(s):

Anne Chetty ◽

Gong-Jie Cao ◽

Mariano Severgnini ◽

Amy Simon ◽

Rod Warburton ◽

...

Keyword(s):

Lung Injury ◽

Structural Changes ◽

Type I Collagen ◽

Alveolar Epithelium ◽

Mouse Lung ◽

Type I ◽

Matrix Metalloprotease ◽

Oxidant Injury ◽

Hyperoxia Exposure

Matrix metalloprotease-9 (MMP-9) is increased in lung injury following hyperoxia exposure in neonatal mice, in association with impaired alveolar development. We studied the role of MMP-9 in the mechanism of hyperoxia-induced functional and histological changes in neonatal mouse lung. Reduced alveolarization with remodeling of ECM is a major morbidity component of oxidant injury in developing lung. MMP-9 mediates oxidant injury in developing lung causing altered lung remodeling. Five-day-old neonatal wild-type (WT) and MMP-9 (−/−) mice were exposed to hyperoxia for 8 days. The lungs were inflation fixed, and sections were examined for morphometry. The mean linear intercept and alveolar counts were evaluated. Immunohistochemistry for MMP-9 and elastin was performed. MMP-2, MMP-9, type I collagen, and tropoelastin were measured by Western blot analysis. Lung quasistatic compliance was studied in anaesthetized mice. MMP-2 and MMP-9 were significantly increased in lungs of WT mice exposed to hyperoxia compared with controls. Immunohistochemistry showed an increase in MMP-9 in mesenchyme and alveolar epithelium of hyperoxic lungs. The lungs of hyperoxia-exposed WT mice had less gas exchange surface area and were less compliant compared with room air-exposed WT and hyperoxia-exposed MMP-9 (−/−) mice. Type I collagen and tropoelastin were increased in hyperoxia-exposed WT with aberrant elastin staining. These changes were ameliorated in hyperoxia-exposed MMP-9 (−/−) mice. MMP-9 plays an important role in the structural changes consequent to oxygen-induced lung injury. Blocking MMP-9 activity may lead to novel therapeutic approaches in preventing bronchopulmonary dysplasia.

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Hydroxyl radical induced structural changes of collagen

Spectroscopy An International Journal ◽

10.1155/2007/496174 ◽

2007 ◽

Vol 21 (2) ◽

pp. 91-103 ◽

Cited By ~ 6

Author(s):

Helan Xiao ◽

Guoping Cai ◽

Mingyao Liu

Keyword(s):

Free Radical ◽

Hydroxyl Radicals ◽

Structural Changes ◽

Type I Collagen ◽

Free Radical Scavenger ◽

Radical Scavenger ◽

Type I ◽

Dependent Manner ◽

First Time

Extracellular matrix (ECM) plays an important role in cell differentiation, growth, migration and apoptosis. Collagen is the most abundant protein familyin vivo, but its function has still not been clearly defined yet. Reactive oxygen species (ROS) have a central role in oxidative cell stress. Electron spin resonance (ESR) spectroscopy indicates that type I collagen could uniquely scavenge hydroxyl radicals in dose- and time-dependent manner; whereas BSA and gelatin (a denatured collagen) have no such an effect. However, the mechanism by which type I collagen scavenges hydroxyl radicals is different from that of GSH, a well-known free radical scavenger. Using a new method, two-dimensional FTIR correlation analysis, for the first time, we show that the order of functional group changes of type I collagen in this process is amide I earlier than amide II than amide III than –CH– thanν(C=O). The results indicates that the structure of the main chain of collagen changed first, followed by more residue groupν(C=O) exposed to hydroxyl radicals. The reaction with the carbonyl group in collagen causes the hydroxyl free radicals to be scavenged. Therefore, ECM can effectively scavenge ROS under normal physiological conditions. When the proteins of ECM were denatured in the same way as gelatin, they lost their function as a free radical scavenger. All of these results provide new insight into therapy or prevention of oxidative stress, apoptosis and ageing.

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A Novel Method for Measuring the Optical Activity of Biopolymers and Application in Measuring Denaturation of Type I Collagen

10.1115/imece2000-2581 ◽

2000 ◽

Author(s):

Alexander J. Majewski ◽

Martin Sanzari

Keyword(s):

Optical Activity ◽

Type I Collagen ◽

Polarization State ◽

Measurement Techniques ◽

Index Of Refraction ◽

Optical Rotatory Dispersion ◽

Type I ◽

Optical Rotatory ◽

Left Handed ◽

New Instrument

Abstract Optical Activity is defined as a property, in which a substance will absorb incident (optical) radiation and / or change its polarization state. Molecules of this type are known as chiral (its mirror image cannot be superimposed upon itself i.e. the molecule has a handedness). Optical Rotatory Dispersion (circular birefringence) occurs when a material exhibits a difference in its index for right-handed (nR) or left-handed (nL) circularly polarized light. In terms of the indices of refraction, the observed rotation is defined as: α = (πd/λo) (nL − nR). Where: nL = index of refraction for left-handed polarization; nR = index of refraction for right-handed polarization; d = path length (sample thickness); λo = wavelength of incident radiation measured in vacuum. We have developed and tested a new instrument that measures the optical rotatory properties of biopolymers. The advantage of this instrument is that it allows a real time measurement of the optical activity of biopolymers; which can be used to monitor samples for changes of state. By using a differential measurement scheme, system errors are minimized and resolution is increased over current measurement techniques. A study of the denaturation process of type I collagen will be presented.

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