Molecular structure of collagen in solution: comparison of types I, II, III and V (original) (raw)
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Effect of Pepsin on Biochemical and Biophysical Studies of Collagen
One of the most important biomaterials under study throughout the world is collagen. Collagen is a large diverse family of fibrous proteins which accounts for about one quarter of total protein mass in our body it is a major extracellular and structural protein. It gives many different organs and tissues substantial stout and elastic properties. It is found in connective tissues such as tendons, hyaline cartilage, organic matrix bones, cornea of the eye, intervertebral disks, vitreous bodies, blood vessels, teeth, skin, placenta, and heart valves. Collagen plays a regulating role in developing tissues and cell type specific gene expression, differentiation of unspecialized cells and disease like cancer. Collagen occurs in the shape of fibres, ropes, straps, woven sheets, filtration membranes, supporting skeletal frame work and bearing materials. Collagen is a rod-shaped molecule of about 3,000 A 0 long and 15A 0 in diameter. Each turn of the helix is made up of nearly 3.3 amino acids and 2.9A 0 height. From this study it was found that the shrinkage of rat tail tendon collagen fibre decreases as the concentration of pepsin increases the shrinkage optical micrographs of native RTT in water and 0.1% pepsin show the swelling behaviour of collagen. The reduction in the fibrillar stability indicates that naturally occurring bi/multifunctional cross links in the end region of the molecules. Which are responsible for the fibrillar stability are cleaved by pepsin. The denaturation temperature indicates the helix to coil transition in collagen. The kinetics of fibril formulation of native collagen shows the regular nucleation and growth phase. In the case of the kinetics of fibril formulation of pepsin treated collagen, there is irregular nucleation and growth phase.
Molecular structure and physical properties of type IV collagen in solution
International Journal of Biological Macromolecules, 1987
The physical properties of intact type IV collagen from the mouse EHS sarcoma were studied in acid solution using laser light scattering and viscometry. The experimentally observed values of molecular weight, translational diffusion coefficient, particle scattering factor at 175.5 ° and a wavelength of 633 nm and intrinsic viscosity at 22°C were 532000, 0.66 x 10-7 cm 2 s-l, 0.492 and 74.7 ml/g respectively. Plots of Kc/Ro versus collagen concentration were linear with a slope of approximately O, indicating that under the conditions studied, type IV collagen molecules do not form supra-molecular aggregates. Experimentally determined translational diffusion coefficients closely approximated the calculated value for a rod-like molecule 424 nm long and 1.5 nm in diameter. Based on this observation, it is concluded that the type I V collagen molecule translates like a bent rigid rod similar to the interstitial collagens. However, the low intrinsic viscosity and larger value of the particle scattering factor for type IV collagen molecules in comparison with the interstitial collagens indicate that type I V collagen is considerably more flexible. Physical measurements on molecules in solution are consistent with a model of the type I V molecule containing numerous flexible bends with bend angles less than 125% It is concluded that the type IV collagen molecule behaves like a worm-like rod in solution.
Biomaterials, 1987
Diffusion of angiotensin II, albumin and aldolase was studied through collagen membranes with swelling ratios between 4 and 15. The diffusion coefficient was measured from the time-lag for the onset of steadystate flux through the membrane. Binding of macromolecules to collagen was evaluated from the results of sorption studies conducted as a function of macromolecular concentration. Results presented indicate that the diffusion of macromolecules through collagen membranes is slowed by electrostatic and hydrogen bonding between individual macromolecular chains and collagen. The extent of adsorption is increased as the molecular weight of the diffusant increases. Diffusion of water soluble macromolecules through collagen occurs rapidly, suggesting that diffusion occurs through water filled channels as opposed to between collagen molecules. The results of these studies are useful in understanding diffusion through connective tissues and in the design of drug delivery systems based on collagen.
Investigations on geometrical features in induced ordering of collagen by small molecules
Journal of Chemical Sciences, 2003
Binding energies of the interaction of collagen like triple helical peptides with a series of polyphenols, viz. gallic acid, catechin, epigallocatechingallate and pentagalloylglucose have been computed using molecular modelling approaches. A correlation of calculated binding energies with the interfacial molecular volumes involved in the interaction is observed. Calculated interface surface areas for the binding of polyphenols with collagen-like triple helical peptides vary in the range of 60-210 Å 2 and hydrogen bond lengths vary in the range of 2⋅7-3⋅4 Å. Interfacial molecular volumes can be calculated from the solvent inaccessible surface areas and hydrogen bond lengths involved in the binding of polyphenols to collagen. Molecular aggregation of collagen in the presence of some polyphenols and chromium (III) salts has been probed experimentally in monolayer systems. The monolayer arrangement of collagen seems to be influenced by the presence of small molecules like formaldehyde, gluteraldehyde, tannic acid and chromium (III) salts. A fractal structure is observed on account of two-dimensional aggregation of collagen induced by tanning species. Atomic force microscopy has been employed to probe the topographic images of two-dimensional aggregation of collagen induced by chromium (III) salts. A case is made that long-range ordering of collagen by molecular species involved in its stabilisation is influenced by molecular geometries involved in its interaction with small molecules.
Effect of Solvent on the Hydrodynamic Properties of Collagen
Polymers, 2021
In this study, the effect of solvent on the hydrodynamic properties of collagen extracted from tail tendons of young rats was researched. Collagen was dissolved in various aqueous carboxylic acid solutions, including acetic acid (AA), acetic acid with the addition of sodium chloride (AA/NaCl), formic acid (FA), lactic acid (LA), citric acid (CA), and also citrate buffer at pH = 3.7 (CB). The properties of collagen solutions at a concentration of 0.45 mg/mL were characterized based on the viscometric method. The reduced viscosity, intrinsic viscosity, and Huggins coefficient of collagen solutions and effect of solvent, temperature, and UV irradiation on these properties were investigated. Collagen solutions in acetic acid, acetic acid/NaCl, and citrate buffer were irradiated with UV light up to 1 h, and the viscosity of collagen solutions was measured. It was found that the organic acids used as solvent affected viscosity behavior, denaturation temperature, and stability of collagen ...
Mechanical response of collagen molecule under hydrostatic compression
Materials Science and Engineering: C, 2015
Proteins like collagen are the basic building blocks of various body tissues (soft and hard). Collagen molecules find their presence in the skeletal system of the body where they bear mechanical loads from different directions, either individually or along with hydroxy-apatite crystals. Therefore, it is very important to understand the mechanical behavior of the collagen molecule which is subjected to multi-axial state of loading. The estimation of strains of collagen molecule along different directions resulting from the changes in hydrostatic pressure magnitude, can provide us new insights into its mechanical behavior. In the present work, full atomistic simulations have been used to study global (volumetric) as well as local (along different directions) mechanical properties of the hydrated collagen molecule which is subjected to different hydrostatic pressure magnitudes. To estimate the local mechanical properties, the strains of collagen molecule along its longitudinal and transverse directions have been acquired at different hydrostatic pressure magnitudes. In spite of non-homogeneous distribution of atoms within the collagen molecule, the calculated values of local mechanical properties have been found to carry the same order of magnitude along the longitudinal and transverse directions. It has been demonstrated that the values of global mechanical properties like compressibility, bulk modulus, etc. as well as local mechanical properties like linear compressibility, linear elastic modulus, etc. are functions of magnitudes of applied hydrostatic pressures. The mechanical characteristics of collagen molecule based on the atomistic model have also been compared with that of the continuum model in the present work. The comparison showed up orthotropic material behavior for the collagen molecule. The information on collagen molecule provided in the present study can be very helpful in designing the future bio-materials.
Diffusion characteristics of collagen film
Journal of Controlled Release, 2001
Collagen films prepared by treating collagen gel solutions with different concentrations of glutaraldehyde were evaluated as a biodegradable and biocompatible drug carrier for cosmetically effective agents in this study. The influences of concentration of glutaraldehyde (0, 0.05, 0.075, 0.1, 0.2, 0.25, and 0.3%, v / w) with a fixed concentration (1%, w / w) of collagen on the crosslinking rate of collagen gel solutions and on the crosslinking extent of the collagen contained within were examined by monitoring changes in viscosity. In addition, the influences of the addition of different model drugs (retinoic acid, retinol palmitate, ascorbic acid 6-palmitate, and tocopherol acetate) on viscosity changes of collagen gel solutions were compared. The results demonstrate that the maximal viscosity of collagen gel solutions increases with increasing concentrations of glutaraldehyde. When the concentration of glutaraldehyde exceeds 0.2%, the maximal viscosity of collagen gel solutions reaches a plateau. However, model drugs showed insignificant effects on viscosity changes of collagen gel solutions. The diffusion characteristics of collagen films prepared from those gel solutions crosslinked with different concentrations of glutaraldehyde were assessed using two different matrix forms of solution or gel for the model drugs in a flow-through diffusion system. The matrix effect on the flux of model drugs from both solution and gel matrix through collagen films was inconclusive. However, both fluxes show the same tendency to decrease when the concentration of glutaraldehyde used for crosslinking is increased. However, when the concentration of glutaraldehyde exceeds 0.2%, these model drugs, except retinoic acid, show similar diffusion characteristics across the collagen films.
Journal of Biological Chemistry
We have measured the diffision coefficient and weight average molecular weight of type I collagen fibril fragments obtained by acid extraction of rat tail tendons and neutral extraction of lathyritic chick skin, using laser light scattering techniques. The molecular weight and translational diffusion coefficient were found to be 8.05 f 0.40 X 10' and 0.450 -C 0.04 X lo-' cm2/s, respectively, for preparations which contain aggregates in 0.01 M HCl, and 2.82 * 0.20 X 10' and 0.780 f 0.04 x lo-' cm2/s for collagen single molecules.
Collagen and Its Modifications-Crucial Aspects with Concern to Its Processing and Analysis
Macromolecular Materials and Engineering, 2017
scaffolds; however, they also make up the key proteins for a range of vital processes at work within the organism. [1] To date, some 30 various types of collagen have been identified. [2] The most abundant collagens consist of so-called fibrilforming collagens (up to 90% of all human collagens) with their characteristic quarter-staggered fibril-array. [3] The most abundant collagens are type I which is present mainly in bone, tendons, skin, dentin, etc., type II mostly in cartilage and type III like in skin. [2] The other minor collagen types are rather organ-specific. Water performs an elemental function in terms of the conservation of the physical properties of collagen. An amount of water at a level of around 20% of the total weight of collagen is necessary for the maintaining of its physical properties. In low hydrated or dehydrated collagen, the polypeptide chains are restricted in their motion; however, with increasing hydration these chains are gradually released. [1] Many connective tissue diseases and defects are associated with poor synthesis or excessive degradation of collagen. The modern tissue engineering approach is to replace the defective site via the implantation of a biocompatible scaffold which serves as a carrier for cell incorporation, proliferation, and growth. Collagen is widely used in the field of clinical medicine in connection with both hard and soft tissue applications. However, certain collagen properties such as poor dimensional stability, poor in vivo mechanical strength, low degree of elasticity, variable nature in terms of enzymatic degradation, crosslinking density, fiber size, trace impurities, and side effects frequently limit both its analysis and application. This review focuses particularly on the processing and modification of collagen type I with respect to its biological and mechanical properties. The processing of collagen into scaffolds is crucial to mimic successfully the extracellular matrices. Moreover, the review suggests several ways in which the most common problems related to the isolation, handling, electrospinning, and crosslinking of collagen can be overcome while maintaining its native character as much as possible. Further, the review provides a summary of the analytical methods available for the physicochemical characterization of collagen with respect to both its molecular and submolecular structure.