CRYSTAL STRUCTURE OF A KUNITZ-TYPE TRYPSIN INHIBITOR FROM ERYTHRINA CAFFRA SEEDS
Crystallization and Preliminary Diffraction Studies of Erythrina Trypsin Inhibitor
VLLDGNGEVVQNGGTYYLLPQVWAQGGGVQLAKTGEETCPLTVVQSPNELSDGKPIRIESRLRSAFIPDDDKVRIGFAYA PKCAPSPWWTVVEDEQEGLSVKLSEDESTQFDYPFKFEQVSDQLHSYKLLYCEGKHEKCASIGINRDQKGYRRLVVTEDY PLTVVLKKDESS
SHEET ETI CONSISTS OF 12 ANTIPARALLEL BETA-STRANDS JOINED BY LONG LOOPS. SIX OF THE STRANDS FORM A SHORT BARREL WHICH IS CLOSED AT ONE END BY A "LID" CONSISTING OF THE OTHER SIX STRANDS COUPLED IN THREE PAIRS. THE MOLECULE SHOWS APPROXIMATE THREE-FOLD SYMMETRY ABOUT THE THE AXIS OF THE BARREL, WITH THE REPEATING UNIT CONSISTING OF FOUR SEQUENTIAL BETA-STRANDS AND THE CONNECTING LOOPS. THE SHEET PRESENTED AS *B1* ON SHEET RECORDS BELOW IS ACTUALLY THE SIX-STRANDED BETA-BARREL. THIS IS REPRESENTED BY A SEVEN-STRANDED SHEET IN WHICH THE FIRST AND LAST STRANDS ARE IDENTICAL.
ERYTHRINA TRYPSIN INHIBITOR (KUNITZ) DE-3