In a study recently published in Nature Chemical Biology, researchers focused on para-nitro-L-phenylalanine (pN-Phe), a non-standard amino acid that is neither one of the twenty standard amino acids nor observed in nature. pN-Phe has been used by other research groups to help the immune system mount a response to proteins that it does not ordinarily respond to.
Click here for original story, Engineers create bacteria that can synthesize an unnatural amino acid
Source: Phys.org