1. c.69.1 alpha/beta-Hydrolases many members have left-handed crossover connection between strand 8 and additional strand 9 ! alpha/beta-Hydrolases core: 3 layers, a/b/a; mixed beta-sheet of 8 strands, order 12435678, strand 2 is antiparallel to the rest 2d81 d2d81a1 A:32-39,224-232,241-249,266-275,275-281 2d81 d2d81a1 A:32-39,224-232,241-249,257-266,275-281 2d80 d2d80a1 A:32-39,224-231,241-249,266-275,275-281 2d80 d2d80a1 A:32-39,224-231,241-249,257-266,275-281