Molecular Chirality of Biosynthesized PHB Translates into Uniformly Curved Single Crystals in Langmuir Films

While in nature, molecular chirality enables the formation of chiral macroscopic structures through crystallization and self-organization, such a transfer of molecular information to higher hierarchical levels is rarely observed in vitro. Here, the study reports on single crystals of microbially synthesized polyester poly[(R)-3-hydroxybutyrate], which have chiral habits when grown at the air-water interface, in analogy to the 2D crystallization of chiral lipids such as DPPC. Depending on the crystallization conditions, the chiral single crystals either undergo a transition into fiber-like structures, orassemble into larger superstructures with a uniform sense of rotation. When poly((R)-3-hydoxybutyrate) crystallizes at low surface pressure in Langmuir films, it forms flat-on crystals with a uniform sense of curvature. While these crystals convert to edge-on crystals under isobaric conditions, elevated temperatures stabilize the flat-on orientation. The flat-on crystals assemble into superstructures with a uniform sense of curvature, enabling the transfer of chirality from the molecular almost to the millimeter scale. image