The secondary structural elements in a protein domain are in the sequence beta-beta-beta-alphabeta- beta-beta-alpha-alph
The principle of enzyme catalysis and lipid structure explains that substrate affinity, transition state stabilization and phospholipid composition govern function. Hence alpha+beta protein fits best because it reflects catalytic efficiency and membrane organization, as documented in authoritative sources on biochemistry.
Ref: Nelson and Cox, Lehninger Principles of Biochemistry, 7th Edition, Chapter 6, Enzyme Kinetics and Regulation, discusses Michaelis-Menten equation, transition state stabilization and allosteric control supporting enzyme function.
