Quasi-hexagonal molecular packing in collagen fibrils

  title={Quasi-hexagonal molecular packing in collagen fibrils},
  author={David J S Hulmes and Andrew D. Miller},
Collagen molecules in native 66.8 nm (D) periodic fibrils are widely believed to be assembled into discrete, rope-like sub-structures, or microfibrils1–17. Several types of microfibril have been proposed (2,4,5,7- and 8-stranded), mainly on the basis of information contained in the medium angle X-ray diffraction patterns of native tendon fibres1,5–7. These patterns show a series of equatorial and near-equatorial Bragg reflections which indicate that the collagen molecules are arranged on a… 
A new model for packing of type-I collagen molecules in the native fibril
A specific fibril model is presented consisting of bundles of five-stranded microfibrils, which are usually disordered but under lateral compression become ordered, and calculated intensities in the equatorial region of the x-ray diffraction pattern agree with observed values.
Molecular packing of type I collagen in tendon.
A global search through combinations of molecular packing and molecular translation revealed that the sheet-type conformations cannot account for the observed low-angle off-meridional Bragg peak intensity distribution.
Compressed microfibril models of the native collagen fibril
Two models which contain five-stranded microfibrils compressed to place molecules (in cross-section) on a pseudo-hexagonal lattice are proposed, which are equivalent or related to the cell proposed by Hulmes and Miller1.
Chemical cross-linking restrictions on models for the molecular organization of the collagen fibre
It is argued here that until other characteristic parameters are taken into account, in particular the chemical cross-linking evidence, the packing problem is still unresolved.
Structure of Collagen Fibrils
Three clear features of the structure of collagen fibrils are recognised and probably not seriously disputed: axially, molecules are related by staggers of integral multiples of approximately 67nm, the near-equatorial X-ray diffraction pattern suggests a structure in an equatorial projection reminiscent of a two dimensional simple liquid, and some parts of the fibril that is crystalline or nearly so are suggested.
Computational study of packing a collagen‐like molecule: Quasi‐hexagonal vs “Smith” collagen microfibril model
The lateral packing of a collagen‐like molecule, CH3CO‐(Gly‐L‐Pro‐ L‐Pro)4‐NHCH3, has been examined by energy minimization with the ECEPP/3 force field and is found to be energetically more favorable than the Smith microfibril model.
Molecular packing in type I collagen fibrils.


Molecular assembly in collagen
The intermolecular space of reconstituted collagen fibrils.
Structural Units in Collagen Fibrils
It is of interest to note that evidence for structure of size approximately 200 A. is found in α-keratin5 and 230 A. in fibrin6, although the recurrence of this figure may be no more than coincidental.
Sequence regularities and packing of collagen molecules.
The crystalline structure of collagen fibrils in tendon.
Modern theories of liquids and the diffuse equatorial X‐ray scattering from collagen
The idea that the lateral arrangement of a proportion of molecules in the collagen fibril displays a short-range two-dimensional liquid-like order is investigated and shown to be true. Theoretical