Topochemistry of the binding of phosphotungstic acid to collagen

Nemetschek, Th.; Riedl, Harald Udo von; Jonak, R.

doi:10.1016/0022-2836(79)90251-1

Cited by 43 publications

(35 citation statements)

References 16 publications

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“…This denotes that these substances bind to the collagenous component of the soft tissue. This affirmation has also been proven in different works from the literature, for example in the works of Nemetschel et al [29], Puchtler and Isler [30] or Watson [31]. Interestingly, these substances could also slightly color the elastin component of the tissue, as noted by Greenlee et al [32].…”

Section: Rationalementioning

confidence: 54%

Assessing the three-dimensional collagen network in soft tissues using contrast agents and high resolution micro-CT: Application to porcine iliac veins

Nierenberger

Rémond

Ahzi

et al. 2015

Comptes Rendus. Biologies

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Section: Rationalementioning

confidence: 54%

Assessing the three-dimensional collagen network in soft tissues using contrast agents and high resolution micro-CT: Application to porcine iliac veins

Nierenberger

Rémond

Ahzi

et al. 2015

Comptes Rendus. Biologies

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“…The diffuse intensity indicates short-range order and is of a different character from the sharp (1/3.8) nm-1 reflections. Above pH 5, the diffuse intensity is greatly diminished, but the (1/3.8) nm-1 row line is relatively intense (35).…”

Section: Resultsmentioning

confidence: 97%

“…Second, the x-ray diffraction pattern of the embedded fiber will be dominated by the stain distribution. The finite size ofthe phosphotungstate moiety (35) will limit the resolution to which the stain distribution can accurately represent the molecular packing. Third, the x-ray diffraction intensities depend on the contrast between the electron density of the scattering unit and the electron density of the environment (3).…”

Section: Resultsmentioning

confidence: 99%

“…Its appearance is associated with phosphotungstic acid staining at low pH (unpublished results; ref. 35) on unstretched specimens. The diffuse intensity indicates short-range order and is of a different character from the sharp (1/3.8) nm-1 reflections.…”

Section: Resultsmentioning

confidence: 99%

“…Freezing before use did not affect either the x-ray diffraction patterns or the electron microscope observations. The fibers were fixed in 4% formaldehyde (pH 3.6, unbuffered) for 2 hr (12,34,35), stained in 1% phosphotungstic acid (pH 2.2, unbuffered) for 1 hr, rinsed briefly in H20, and stained in 1% uranyl acetate for 1 hr. The fibers were then dehydrated over a period of 2 hr in graded acetone/H20 mixtures.…”

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Electron microscopy shows periodic structure in collagen fibril cross sections.

Hulmes¹,

Jésior²,

Miller³

et al. 1981

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

100

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X-ray diffraction was used to monitor the effects of electron microscope fixation, staining, and embedding procedures on the preservation of the three-dimensional crystalline order in collagen fibrils of rat tail tendon. A procedure is described in which the characteristic 3.8-nm lateral spacing is preserved, with increased contrast, in the diffraction pattern ofthe embedded fiber. This spacing is correlated with the separation between the tangentially oriented equally spaced lines of density observed in electron microscope ultrathin fibril cross sections of the same material. Optical diffraction of electron micrographs gives an objective measure of the periodicity and suggests that the fibril is composed of concentrically oriented crystalline domains. These observations, when combined with a recent interpretation of the native x-ray diffraction data [Hulmes, D. J. Nature (London) 282, 878-880] suggest a tentative model for the three-dimensional structure of collagen fibrils.The one-dimensional or axially projected structure of collagen fibrils is well understood, to the resolution of individual amino acids (1-5), in terms of the modified "quarter stagger" theory for the molecular packing (6, 7). However, the way in which this scheme is extended into three dimensions remains controversial (for review, see refs. 8 and 9). X-ray diffraction from tendon fibers (10-12) indicates three-dimensional crystallinity in the molecular packing although, in some specimens, only the onedimensional 67-nm (D) axial periodicity has been observed (13,14). Collagen fibrils are somewhat analogous to liquid crystals (15)(16)(17), and the one-dimensionally ordered and three-dimensionally ordered phases may correspond to a smectic A -) B transition. Several interpretations have been suggested for the near-equatorial (i.e., perpendicular to the fiber axis) crystalline x-ray data (8, 9), but recently both the observed spacings and the general intensity distribution have been accounted for by quasi-hexagonal packing of straight tilted molecules (9, 18). In contrast to most of the tetragonal packing schemes, the quasihexagonal model does not require the presence ofthe rope-like intermediate substructures, a few molecules in cross section, called microfibrils.Electron microscopy, particularly on negatively stained specimens, indicates that collagen fibrils have a filamentous substructure (19,20). Filaments have also been observed during in vitro collagenfibrillogenesis (21-23). Estimates of filament width vary from 1.5 nm to 4 nm, and so it has been suggested that these filaments correspond to either individual molecules (18,19) To date, no concerted attempt has been made to correlate electron microscopic data with the x-ray diffraction observations that indicate three-dimensional crystallinity in collagen fibrils. So far, there has been no evidence from electron microscopy for long-range lateral order in the native molecular packing. In this paper, we describe the initial results of an extensive joint x-ray diffraction-electron ...

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Metal Compounds as Enzyme Inhibitors

Gasser

Metzler‐Nolte

2011

Bioinorganic Medicinal Chemistry

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Topochemistry of the binding of phosphotungstic acid to collagen

Cited by 43 publications

References 16 publications

Assessing the three-dimensional collagen network in soft tissues using contrast agents and high resolution micro-CT: Application to porcine iliac veins

Assessing the three-dimensional collagen network in soft tissues using contrast agents and high resolution micro-CT: Application to porcine iliac veins

Electron microscopy shows periodic structure in collagen fibril cross sections.

Metal Compounds as Enzyme Inhibitors

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