SHEET DETERMINATION METHOD: AUTHOR DETERMINED THROUGH ELECTRON DENSITY AND D2O EXCHANGE EXPERIMENTS. ...SHEET DETERMINATION METHOD: AUTHOR DETERMINED THROUGH ELECTRON DENSITY AND D2O EXCHANGE EXPERIMENTS.THE SHEET STRUCTURE OF THIS MOLECULE IS NOT A 3 STRANDS BETA-SHEET BUT A 4 STRANDS BETA-SHEET IN WHICH STRAND 3 IS SPLITTED INTO STRANDS 3 AND 4. IN ORDER TO REPRESENT THIS FEATURE IN THE SHEET RECORD BELOW, TWO SHEETS ARE DEFINED. STRANDS 1, 2, 3 AND 4 OF SHEET *A* AND *B* ARE IDENTICAL.