Synchrotron X-ray diffraction study of corneal stroma

Sayers, Zehra; Koch, Michel H. J.; Whitburn, Susan B.; Meek, Keith Michael Andrew; Elliott, G.F.; Harmsen, Arnold

doi:10.1016/0022-2836(82)90317-5

Cited by 68 publications

(45 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The isolation procedure produces a stable suspension of collagen fibrils that do not aggregate or fuse. The fibril was typical of those isolated from cornea in that it was Ϸ36 nm in diameter (29,30) and exhibited the usual 67-nm D-periodicity of collagen fibrils. Three stain-excluding domains that repeated D-period were distinguishable in each D-period; one domain corresponded to the C-telopeptides of collagen, one domain corresponded to the Ntelopeptides of collagen, and one domain was in the gap (stainfilled) zone of the fibril.…”

Section: Resultsmentioning

confidence: 85%

Corneal collagen fibril structure in three dimensions: Structural insights into fibril assembly, mechanical properties, and tissue organization

Holmes

Gilpin

Baldock

et al. 2001

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

214

142

View full text Add to dashboard Cite

The ability of the cornea to transmit light while being mechanically resilient is directly attributable to the formation of an extracellular matrix containing orthogonal sheets of collagen fibrils. The detailed structure of the fibrils and how this structure underpins the mechanical properties and organization of the cornea is understood poorly. In this study, we used automated electron tomography to study the three-dimensional organization of molecules in corneal collagen fibrils. The reconstructions show that the collagen molecules in the 36-nm diameter collagen fibrils are organized into microfibrils (Ϸ4-nm diameter) that are tilted by Ϸ15°to the fibril long axis in a right-handed helix. An unexpected finding was that the microfibrils exhibit a constant-tilt angle independent of radial position within the fibril. This feature suggests that microfibrils in concentric layers are not always parallel to each other and cannot retain the same neighbors between layers. Analysis of the lateral structure shows that the microfibrils exhibit regions of order and disorder within the 67-nm axial repeat of collagen fibrils. Furthermore, the microfibrils are ordered at three specific regions of the axial repeat of collagen fibrils that correspond to the N-and C-telopeptides and the d-band of the gap zone. The reconstructions also show macromolecules binding to the fibril surface at sites that correspond precisely to where the microfibrils are most orderly.automated electron tomography ͉ microfibril ͉ filaments T he cornea is a highly specialized tissue that combines optical transparency with mechanical resilience. These properties are directly attributable to the formation of an extracellular matrix containing narrow-diameter (Ϸ36 nm) and heterotypic collagen fibrils that are spaced and organized uniformly into sheets of parallel fibrils. Each sheet is arranged orthogonal to its neighbor and to the path of light through the cornea. We reasoned that an understanding of the morphogenesis of the corneal stroma requires detailed knowledge of the structure of individual collagen fibrils.Corneal fibrils are D-periodic (axial periodicity of collagen fibrils, where D Ϸ67 nm), uniformly narrow (Ϸ30-35 nm in diameter), and indeterminate in length, particularly in older animals. The D-periodicity of the fibril arises from side-to-side associations of triple-helical collagen molecules that are Ϸ300 nm in length (i.e., the molecular length ϭ 4.4 ϫ D) and are staggered by D. The D-stagger of collagen molecules produces alternating regions of protein density in the fibril, which explains the characteristic gap and overlap appearance of fibrils negatively contrasted for transmission electron microscopy. Previous attempts to study the high-resolution structure of collagen fibrils have used primarily x-ray fiber diffraction of rat tail tendon (e.g., ref. 1 and references therein) and lamprey notochord (2) in which the fibrils are aligned and composed mostly of one genetic type of collagen. This method has yielded information about the triple...

show abstract

Section: Resultsmentioning

confidence: 85%

Corneal collagen fibril structure in three dimensions: Structural insights into fibril assembly, mechanical properties, and tissue organization

Holmes

Gilpin

Baldock

et al. 2001

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

214

142

View full text Add to dashboard Cite

show abstract

“…By extrapolating this line to H ¼ 0, it is possible to plot a theoretical graph of the expected interfibril spacing on the assumption that all the water entering the stroma has gone towards separating the constituent fibrils. 5,21 This theoretical plot is shown in Figure 5 (line b). The shading around the theoretical plot is the uncertainty owing to the uncertainty in determining the spacing at H ¼ 0 from the experimental data.…”

Section: Direct Summation Of Fields Methodsmentioning

confidence: 88%

“…However, both electron microscopy and X-ray diffraction do not show the presence of this regular packing of collagen fibrils. 4,5 Table 1 shows these two models alongside the other main models, which are all based on Maurice's early work. Hart and Farrell 4 showed that only short-range order in the positions of the collagen fibrils is necessary for the required destructive interference of scattered photons.…”

Section: Corneal Transparencymentioning

confidence: 99%

“…Results from X-ray diffraction showed that the type of short-range order in the packing seen in electron micrographs is indeed what is found in the tissue. 5 Feuk 6 developed a long-range order model based on small, random displacements of the fibrils from ideal lattice sites. Twersky,7 assuming that the fibrils were arranged as in a two-dimensional fluid, expressed the distribution explicitly in terms of the volume fraction occupied by the fibrils.…”

Section: Corneal Transparencymentioning

confidence: 99%

See 1 more Smart Citation

Transparency, swelling and scarring in the corneal stroma

Meek

Leonard

Connon

et al. 2003

Eye

198

132

View full text Add to dashboard Cite

“…This work led to two successive NIH grants, and several ground-breaking publications. Gerald's ideas about the polyelectrolytic nature of the cornea and maintenance of transparency have long been accepted, and are seen as mainstream within the eye field Sayers et al 1982).…”

Section: The Open Universitymentioning

confidence: 99%

Obituary: Professor Gerald Elliott

Squire

2013

J Muscle Res Cell Motil

View full text Add to dashboard Cite

Synchrotron X-ray diffraction study of corneal stroma

Cited by 68 publications

References 23 publications

Corneal collagen fibril structure in three dimensions: Structural insights into fibril assembly, mechanical properties, and tissue organization

Corneal collagen fibril structure in three dimensions: Structural insights into fibril assembly, mechanical properties, and tissue organization

Transparency, swelling and scarring in the corneal stroma

Obituary: Professor Gerald Elliott

Contact Info

Product

Resources

About