SHC is widely conserved in known SHCs. Increases in steric bulk (A306T and A306V) led to the accumulation of 6,6,6,5‐fused tetracyclic scaffolds with 20R stereochemistry. This indicates folding of squalene in a chair‐chair‐chair‐boat conformation. The stereochemical fate in polycyclization is thus governed by the bulk at this position.
Polycyclization和构象分析:Ala306在A.热
硫化叶菌SHC广泛保守已知的特困家庭。空间体积(A306T和A306V)的增加导致具有20 R立体
化学的6,6,6,5融合的四环支架的积累。这表明
角鲨烯折叠成椅子-椅子-船构型。因此,多环化中的立体
化学命运受该位置的主体支配。