Controlling Supramolecular Assembly through Peptide Chirality

Imagine a soft, somewhat gelatinous substance, that can assemble itself. It’s made of short sections of protein that interconnect like microscopic Lego pieces to create a new material.

Researchers set out to test how a tiny change to the structure of those sections would affect outcomes. This change is called chirality. Think of it like a right hand vs. a left hand: exact mirror images.
When examining four different variations of a protein, the researchers found that each behaved differently. Some of the variations link up quickly and create a firm gel within minutes. Others are slower: They start out as small balls, disperse, rearrange, and only a while later form a delicate mesh of nanofibers.

This slow process in fact yielded an advantage. It allows for more uniform dispersal of materials within the gel, an especially important property when introducing drugs or sensitive enzymes, which may be damaged in non-uniform conditions.

The big surprise was that all gels, whether formed rapidly or slowly, and whether soft or firm, managed to prevent oxygen diffusion – thus protecting sensitive enzymes, which tend to spoil in contact with oxygen. When the researchers incorporated a hydrogen-producing enzyme into the gel, it continued to operate normally, as if the oxygen wasn’t there.

This study illustrates how a minute change to molecular structure can yield a wide range of properties, opening the door to developing smart materials: Materials that self-constitute, carry medications, protect delicate substances, and precisely adapt themselves to purpose.

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