A class of non-natural amino acids
that fold into secondary structure
elements such as beta sheets
and alpha helices
the same way the twenty natural amino acids due. Beta-amino acids make up beta-peptides. Each beta-amino acid has an additional carbon in the polypeptide backbone
They are synthesized and used by protein engineers as potential building blocks for biomimetic substrates. The idea is that if you use beta-peptides instead of natural ones, they may similar enough to interact with other proteins, while being different enough to inhibit processes. (an analogy would be a key that is not quite a perfect fit and when you put it in the door, it gets stuck, thereby rendering the door useless.) The same way, a beta-peptide might interact with some disease causing protein in such a way that it ties it up and prevents it from carrying out its natural function.
Another advantage to beta-peptides is that they may be resistant to protein degrading proteins (proteases). As a result, if they are used as drugs in disease therapy, they wont be broken down by the body as quickly as natural peptide products.