The supramolecular structure of bone: X-ray scattering analysis and lateral structure modeling

The evolution of vertebrates required a key development in supramolecular evolution: internally mineralized collagen fibrils. In bone, collagen molecules and mineral crystals form a nanocomposite material comparable to cast iron in tensile strength, but several times lighter and more flexible. Current understanding of the internal nanoscale structure of collagen fibrils, derived from studies of rat tail tendon (RTT), does not explain how nucleation and growth of mineral crystals can occur inside a collagen fibril. Experimental obstacles encountered in studying bone have prevented a solution to this problem for several decades. This report presents a lateral packing model for collagen molecules in bone fibrils, based on the unprecedented observation of multiple resolved equatorial reflections for bone tissue using synchrotron small-angle X-ray scattering (SAXS; ∼1 nm resolution). The deduced structure for pre-mineralized bone fibrils includes features that are not present in RTT: spatially discrete microfibrils. The data are consistent with bone microfibrils similar to pentagonal Smith microfibrils, but are not consistent with the (nondiscrete) quasi-hexagonal microfibrils reported for RTT. These results indicate that collagen fibrils in bone and tendon differ in their internal structure in a manner that allows bone fibrils, but not tendon fibrils, to internally mineralize. In addition, the unique pattern of collagen cross-link types and quantities in mineralized tissues can be can be accounted for, in structural/functional terms, based on a discrete microfibril model.

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Structural transformation of collagen fibrils in corneal stroma during drying. An x-ray scattering study

Biophysical Journal ◽

10.1016/s0006-3495(93)81487-5 ◽

1993 ◽

Vol 64 (4) ◽

pp. 1210-1214 ◽

Cited By ~ 81

Author(s):

P. Fratzl ◽

A. Daxer

Keyword(s):

Structural Transformation ◽

Corneal Stroma ◽

Collagen Fibrils ◽

X Ray ◽

X Ray Scattering ◽

Scattering Study ◽

Ray Scattering

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Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Journal of Applied Physics ◽

10.1063/1.4906325 ◽

2015 ◽

Vol 117 (4) ◽

pp. 044701 ◽

Cited By ~ 21

Author(s):

Hannah C. Wells ◽

Katie H. Sizeland ◽

Hanan R. Kayed ◽

Nigel Kirby ◽

Adrian Hawley ◽

...

Keyword(s):

Small Angle ◽

Poisson’S Ratio ◽

Bovine Pericardium ◽

Collagen Fibrils ◽

Poisson's Ratio ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Can sodium silicates affect collagen structure during tanning? Insights from small angle X-ray scattering (SAXS) studies

RSC Advances ◽

10.1039/c7ra01160a ◽

2017 ◽

Vol 7 (19) ◽

pp. 11665-11671 ◽

Cited By ~ 9

Author(s):

Yi Zhang ◽

Bridget Ingham ◽

Jérôme Leveneur ◽

Soshan Cheong ◽

Yin Yao ◽

...

Keyword(s):

Conformational Changes ◽

Small Angle ◽

Silica Coating ◽

Collagen Structure ◽

X Ray ◽

Leather Processing ◽

X Ray Scattering ◽

Collagen Molecules ◽

Sodium Silicates ◽

Ray Scattering

Sodium silicates can pseudo-stabilize collagen molecules during leather processing by preventing collagen molecules from undergoing conformational changes due to the silica coating on the fibrils.

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Small-angle X-ray scattering of air-dried kangaroo tail tendon

Journal of Polymer Science Polymer Chemistry Edition ◽

10.1002/pol.1981.170191211 ◽

1981 ◽

Vol 19 (12) ◽

pp. 3165-3172 ◽

Cited By ~ 2

Author(s):

T. Misra ◽

K. C. Patra ◽

T. Patel

Keyword(s):

Small Angle ◽

X Ray ◽

X Ray Scattering ◽

Tail Tendon ◽

Ray Scattering

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Simulation of small-angle x-ray scattering from collagen fibrils and comparison with experimental patterns

Physics in Medicine and Biology ◽

10.1088/0031-9155/50/22/012 ◽

2005 ◽

Vol 50 (22) ◽

pp. 5401-5416 ◽

Cited By ~ 24

Author(s):

Heikki Suhonen ◽

Manuel Fernández ◽

Ritva Serimaa ◽

Pekka Suortti

Keyword(s):

Small Angle ◽

Collagen Fibrils ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Small-angle X-ray scattering study of intramuscular fish bone: collagen fibril superstructure determined from equidistant meridional reflections

Journal of Applied Crystallography ◽

10.1107/s0021889808000277 ◽

2008 ◽

Vol 41 (2) ◽

pp. 252-261 ◽

Cited By ~ 27

Author(s):

Christian Burger ◽

Hong-wen Zhou ◽

Igors Sicŝ ◽

Benjamin S. Hsiao ◽

Benjamin Chu ◽

...

Keyword(s):

Small Angle ◽

Collagen Fibril ◽

Axial Direction ◽

Fish Bone ◽

Preferred Orientation ◽

Bone Collagen ◽

X Ray ◽

X Ray Scattering ◽

Transmission Electron ◽

Ray Scattering

New insights into the bone collagen fibril superstructure have been obtained by novel small-angle X-ray scattering analysis. The analysis was carried out on the small-angle equidistant meridional reflections resulting from the periodic structure of collagen fibrils in their axial direction. Conventional two-dimensional analysis is difficult because of the large discrepancy of longitudinal and lateral length scales for individual fibrils, as well as their preferred orientation. The new approach represents an unapproximated analysis of the equidistant meridional reflections, which takes the exact separation of preferred orientation and fibril size effects into account. The analytical results (e.g.axial period, fibril diameteretc.) agree well with the parameters obtained from transmission electron microscopy.

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Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077402 ◽

1983 ◽

Vol 41 ◽

pp. 766-767

Author(s):

Eva-Maria Mandelkow ◽

Eckhard Mandelkow ◽

Joan Bordas

Keyword(s):

Electron Microscopy ◽

Dynamic Equilibrium ◽

Time Resolved ◽

X Ray ◽

Additional Information ◽

X Ray Scattering ◽

Low Concentrations ◽

Microtubule Growth ◽

Ray Patterns ◽

Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181269 ◽

1990 ◽

Vol 48 (1) ◽

pp. 502-503

Author(s):

Eva-Maria Mandelkow ◽

Ron Milligan

Keyword(s):

Electron Microscopy ◽

Dynamic Instability ◽

Entire Solution ◽

Reaction Scheme ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

A Chain ◽

Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

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