Effects of pH and ionic strength on the structure of collagen fibrils

✍ Scribed by A. Ripamonti; N. Roveri; D. Braga; D. J. S. Hulmes; A. Miller; P. A. Timmins

• Publisher: Wiley (John Wiley & Sons)
• Year: 1980
• Tongue: English
• Weight: 566 KB
• Volume: 19
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1980.360190503

✦ Synopsis

Abstract

The roles of pH and ionic strength on the structure and stability of collagen fibrils have been investigated by means of x‐ray and neutron diffraction techniques. High‐angle x‐ray diffraction shows that a salt concentration of 0.5__M__ KCl is sufficient to reduce the osmotic swelling and related disordering in the pH range 1–3. The relative intensities of the low‐angle meridional x‐ray and neutron diffraction Bragg reflections vary with pH. Difference Fourier syntheses between pH 7 and 1.6 data indicate, for both x‐ray and neutron diffraction, a reduced scattering contribution from the telopeptides at low pH. Lyotropic relaxation is a crucial step in the appearance at low pH of a doubling of the 668‐Å axial periodicity (D) of collagen fibrils. These results suggest that electrostatic interactions are essential for the structural stability of the telopeptide regions and of the 1__D__ and 3__D__ intermolecular staggers between collagen molecules.