Collagen packing and mineralization. An x-ray scattering investigation of turkey leg tendon

Fratzl, Peter; Fratzl‐Zelman, Nadja; Klaushofer, Klaus

doi:10.1016/s0006-3495(93)81362-6

Cited by 157 publications

(114 citation statements)

References 21 publications

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“…Thus, whereas the single-bond binding free energy is slightly greater on the (110) face, the binding energy for the full collagen triple helix is ∼20% larger on the (100) face, suggesting that the stereochemical relationship of collagen to HAP favors better multisite binding on HAP (100) than on HAP (110). [1][2][3][4][5][6][7][8][9][10], and [1][2][3][4][5][6][7][8][9][10][11][12][13] vectors. HAP is a dipolar crystal, constructed of layers of alternating net positive-negative charge that define apparent natural cleavage planes parallel to (100).…”

Section: Results and Analysismentioning

confidence: 99%

Energetic basis for the molecular-scale organization of bone

Tao

Battle

Pan

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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The remarkable properties of bone derive from a highly organized arrangement of coaligned nanometer-scale apatite platelets within a fibrillar collagen matrix. The origin of this arrangement is poorly understood and the crystal structures of hydroxyapatite (HAP) and the nonmineralized collagen fibrils alone do not provide an explanation. Moreover, little is known about collagen-apatite interaction energies, which should strongly influence both the molecular-scale organization and the resulting mechanical properties of the composite. We investigated collagen-mineral interactions by combining dynamic force spectroscopy (DFS) measurements of binding energies with molecular dynamics (MD) simulations of binding and atomic force microscopy (AFM) observations of collagen adsorption on single crystals of calcium phosphate for four mineral phases of potential importance in bone formation. In all cases, we observe a strong preferential orientation of collagen binding, but comparison between the observed orientations and transmission electron microscopy (TEM) analyses of native tissues shows that only calcium-deficient apatite (CDAP) provides an interface with collagen that is consistent with both. MD simulations predict preferred collagen orientations that agree with observations, and results from both MD and DFS reveal large values for the binding energy due to multiple binding sites. These findings reconcile apparent contradictions inherent in a hydroxyapatite or carbonated apatite (CAP) model of bone mineral and provide an energetic rationale for the molecular-scale organization of bone.biomineralization | bone | protein-mineral interface | dynamic force spectroscopy B one is a natural protein-mineral composite consisting of nonstoichiometric nanometer-scale carbonated apatite crystallites inside a fibrillar protein matrix. The matrix is mainly composed of type I collagen and is organized on multiple length scales (1, 2). At the shortest scale, three polypeptide chains form a triple helix referred to as a tropocollagen molecule that is ∼300 nm in length and 1.5 nm in diameter. These helices are arranged in a quasi-hexagonal bundle in which they overlap and intertwine to form microfibrils containing "hole zones," where there is a gap between the N termini of one helix and the C termini of another (3-5). These microfibrils are further bundled both laterally and longitudinally to form native collagen (3, 4).Within this highly organized scaffold, apatite crystallites form nanometer-scale platelets (6-9) with their [001] axes preferentially aligned parallel to the fibril axis (10-15) and the platelet faces defined by {100} crystal planes (16). Recent in vitro investigations of hydroxyapatite (HAP) formation within collagen fibrils revealed a multistage process in which amorphous calcium phosphate (ACP) first infiltrated through the hole zones and then converted into HAP platelets with initial mineral deposition occurring near the hole zones (11, 13). In vitro transmission electron microscopy (TEM) and atomic force microscop...

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Section: Results and Analysismentioning

confidence: 99%

Energetic basis for the molecular-scale organization of bone

Tao

Battle

Pan

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Lees and Fratzl et al (Lees, 1981;Fratzl et al, 1993) reported that the effective molecular diameter of dry TC molecules is 1.09 nm and that of wet TC molecules is about 1.42-1.5 nm. Hydration affects the packing, as molecules are closer, and the sliding between molecules becomes more difficult due to increased adhesion.…”

Section: Mineralized Collagen Microfibrilmentioning

confidence: 99%

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

Barkaoui¹,

Hambli²,

Tavares³

2014

Computer Methods in Biomechanics and Biomedical Engineering

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Bone is a multiscale heterogeneous material and its principal function is to support the body structure and to resist mechanical loads without fracturing. Numerical modelling of biocomposites at different length scales provides an improved understanding of the mechanical behaviour of structures such as bone, and also guides the development of multiscale mechanical models. Here, a three-dimensional nano-scale model of mineralized collagen microfibril based on the finite element method was employed to investigate the effect of material and structural factors on the mechanical equivalent of fracture properties.

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“…4). In this model, collagen molecules are represented by 1.1 nm hard disks that are arranged in a quasihexagonal lattice (14) at packing densities corresponding to those seen for fully hydrated and dry collagen fibrils (22,24). It is readily apparent from this model that molecules the size of glucose can freely diffuse into all of the water in the lateral plane of the hydrated fibril.…”

Section: Test Molecule Massmentioning

confidence: 99%

“…Hydration has no measurable impact on the axial structure of the fibril, which has the same 67 nm periodicity in dry and fully hydrated collagen fibrils (23). In contrast, hydration progressively increases the Bragg spacing between adjacent collagen molecules in the lateral plane, from 1.1 nm in the dry fibril to 1.8 nm when the fibril is fully hydrated (24). In the lateral plane, each collagen molecule is therefore separated from its neighbors by a water layer 6 -7 Å thick (22).…”

mentioning

confidence: 99%

The Size Exclusion Characteristics of Type I Collagen

Toroian

Lim

Price

2007

Journal of Biological Chemistry

219

113

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The mineral in bone is located primarily within the collagen fibril, and during mineralization the fibril is formed first and then water within the fibril is replaced with mineral. The collagen fibril therefore provides the aqueous compartment in which mineral grows. Although knowledge of the size of molecules that can diffuse into the fibril to affect crystal growth is critical to understanding the mechanism of bone mineralization, there have been as yet no studies on the size exclusion properties of the collagen fibril. To determine the size exclusion characteristics of collagen, we developed a gel filtration-like procedure that uses columns containing collagen from tendon and bone. The elution volumes of test molecules show the volume within the packed column that is accessible to the test molecules, and therefore reveal the size exclusion characteristics of the collagen within the column. These experiments show that molecules smaller than a 6-kDa protein diffuse into all of the water within the collagen fibril, whereas molecules larger than a 40-kDa protein are excluded from this water. These studies provide an insight into the mechanism of bone mineralization. Molecules and apatite crystals smaller than a 6-kDa protein can diffuse into all water within the fibril and so can directly impact mineralization. Although molecules larger than a 40-kDa protein are excluded from the fibril, they can initiate mineralization by forming small apatite crystal nuclei that diffuse into the fibril, or can favor fibril mineralization by inhibiting apatite growth everywhere but within the fibril.

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Collagen packing and mineralization. An x-ray scattering investigation of turkey leg tendon

Cited by 157 publications

References 21 publications

Energetic basis for the molecular-scale organization of bone

Energetic basis for the molecular-scale organization of bone

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

The Size Exclusion Characteristics of Type I Collagen

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