X-ray analysis of renin substrates. Phenyloxyacetyl-leucyl-valyl-phenylalanine methyl ester: an analogue of angiotensinogen-(10-13) sequence.

The crystal structure of the title compound, an analogue of the angiotensinogen-(10-13) peptide in which the N-terminal leucine and the C-terminal tyrosine are respectively replaced by the phenyloxy-acetic group and by phenylalanine, has been determined by X-ray diffraction. The peptide crystallizes in the space group P2(1)2(1)2(1) with a = 4.866(1), b = 22.311(3), c = 27.213(4) A and Z = 4. The crystal structure was solved by direct methods and refined to an R value of 0.056. The molecules adopt a pleated sheet conformation with the hydrophobic residues alternatively situated on the right and left of the main chain. In the crystallographic "a" direction, the molecules are linked by hydrogen bonds and form parallel pleated sheet-type structures.