Abstract:
:The ultrastructure of the crystalline ferric mineral that forms the central core of ferritin macro-molecules has been examined by means of ultrahigh resolution electron microscopy at 100 kV. Very high magnification dark-field images reveal the presence of either a single large crystal or several smaller crystallites within many of the cores. When the highly crystalline core contents are suitably oriented to transmit their Bragg reflections through the objective aperture, regular fringes separated by 2-9.5 A have been visualized. The geometrical relations of lattice fringes and of periodically organized point details in these individual crystallites largely confirm the structural model proposed by Towe and Bradley (1967). The highly variable occupancy of ferric ions in certain planes of the lattice suggests that 20-33% of the iron content of fully saturated ferritin should undergo more rapid physiological release than does the remainder, and that iron uptake will have kinetics that depend upon more than only the maximal rate of crystallization.
journal_name
Proc Natl Acad Sci U S Aauthors
Massover WH,Cowley JMdoi
10.1073/pnas.70.12.3847subject
Has Abstractpub_date
1973-12-01 00:00:00pages
3847-51issue
12eissn
0027-8424issn
1091-6490journal_volume
70pub_type
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