Jenkins J, Tickle I, Sewell T, Ungaretti L, Wollmer A, Blundell T
Adv Exp Med Biol. 1977;95:43-60. doi: 10.1007/978-1-4757-0719-9_4.
The structure of an acid proteinase from Endothia parasitica has been solved by x-ray diffraction using multiple isomorphous replacement. A 3 A resolution map was interpreted in terms of a bilobal structure with a long 25 A cleft. The secondary structure is mostly distorted beta-sheet. The circular dichroism was measured and model curves for different secondary structures were fitted by least squares indicating a large component of beta-structure. The structure was seen to be homologous with that of the acid proteinase from R. Chinensis and hence with pepsin and chymosin. A rotation function against diffraction data from chymosin crystals confirm confirm this and suggested an approach to the solution of this structure.
