title: Experimental confirmation of calculated phases and electron density profile for wet native collagen.
abstract: An experimental procedure is developed to phase the reflections obtained in x-ray diffraction investigations of collagen in native wet tendons. Phosphotungstic acid was used for isomorphous addition in phase determination and was located by electron microscopy. Structure factors (with phases) were obtained from the electron microscopy data for the heavy metal. Structure-factor magnitudes for collagen with and without the heavy metal were obtained from the x-ray diffraction data. The first 10 orders were investigated. Standard Argand diagrams provided two solutions for each of these, except the weak sixth order. In each case, one of the two possible solutions agrees well with the phases proposed on theoretical grounds by Hulmes et al. The present results suggest that their other proposed phases are probably correct. An electron density profile along the unit cell of the fibril is presented that shows a distinct step, as expected on the basis of the hole-overlap model. The overlap region is 48% of the length of the unit cell.
mesh_terms: D000818:Animals; D003094:Collagen; D004372:Ducks; D008433:Mathematics; D008854:Microscopy, Electron; D011487:Protein Conformation; D013710:Tendons / Q000032:analysis; D014961:X-Ray Diffraction
chemical_list: D003094:Collagen
references.citation: J Biophys Biochem Cytol. 1961 Feb;9:409-14
references.pmid: 13764136
references.citation: Biophys J. 1966 May;6(3):305-12
references.pmid: 5963461
references.citation: FEBS Lett. 1970 Nov 18;11(2):105-108
references.pmid: 11945461
references.citation: Eur J Biochem. 1977 Dec;81(3):599-607
references.pmid: 598383
references.citation: Mol Cell Biochem. 1975 Sep 30;8(3):141-57
references.pmid: 171554
references.citation: Biophys J. 1977 Jul;19(1):63-70
references.pmid: 880321
references.citation: Biochem Biophys Res Commun. 1974 Sep 23;60(2):858-64
references.pmid: 4421386
references.citation: Proc R Soc Lond B Biol Sci. 1974 May 7;186(1082):67-74
references.pmid: 4151227
references.citation: Biophys J. 1973 Oct;13(10):1030-48
references.pmid: 4748375
references.citation: J Mol Biol. 1961 Oct;3:483-506
references.pmid: 14491907
references.citation: J Mol Biol. 1974 Feb 25;83(2):275-80
references.pmid: 4821873
references.citation: J Mol Biol. 1973 Sep 5;79(1):137-48
references.pmid: 4745843
references.citation: Biochim Biophys Acta. 1973 Nov 11;328(1):213-20
references.pmid: 4761989
references.citation: Proc R Soc Lond B Biol Sci. 1974 Aug 27;187(1086):37-46
references.pmid: 4153854
references.citation: J Ultrastruct Res. 1970 Aug;32(3):191-211
references.pmid: 4195855
references.citation: J Mol Biol. 1977 Mar 15;110(4):643-66
references.pmid: 859177
references.citation: Connect Tissue Res. 1974;2(2):137-50
references.pmid: 4138005
references.citation: J Mol Biol. 1975 Jan 5;91(1):79-99
references.pmid: 127048
references.citation: Annu Rev Biochem. 1974;43(0):567-603
references.pmid: 4605221
references.citation: Biophys J. 1978 Dec;24(3):613-28
references.pmid: 83884
references.citation: Nature. 1965 Aug 21;207(999):822-6
references.pmid: 5885940