CRYSTAL PACKING OF THYROGLOBULIN

The molecular packing in 19 s thyroglobulin crystals has been examined using shadowed, positively stained and negatively stained preparations. Crystallizing thyroglobulin molecules first form polymers which are right-handed helices with an average pitch of 228 Å having four molecules per turn. The molecular shape appears to be approximately a sphere of 114 Å diameter or a prolate ellipsoid of comparable volume. The three-dimensional packing of the helices can be described by an octamolecular orthorhombic unit cell having sides of 395, 228 and 197 Å. © 1968.