Proteins from non-proteinogenic amino acids grow on super yeast
Researchers from the USA genetically modified yeast cells, giving them the ability to produce significant amounts of proteins containing residues of non–proteinogenic amino acids (unnatural amino acids, UAA) - only bacteria previously possessed this ability.
All organisms form proteins from 20 proteinogenic amino acids, but proteins containing synthetic UAA may have potentially useful biological properties. Some of them exhibit fluorescence, which allows you to observe their movement through the cell, some have potential therapeutic properties.
In the picture:
genetically modified yeast expresses a green fluorescent protein, which includes the remains of two non-proteinogenic amino acids (left);
two non-proteinogenic amino acids used by the researchers (right).
Lei Wang and Qian Wang from the San Diego Institute (California) have developed a method for obtaining large amounts of such proteins in significant quantities using genetically modified yeast.
The researchers approached the solution of this problem from two directions. Initially, with the help of genetic engineering, they obtained yeast capable of obtaining bacterial transport RNA responsible for the transfer of UAA more efficiently. After that, the "protective systems" responsible for blocking the introduction of UAA into the protein were removed from the yeast cells.
The combination of approaches allowed to increase by 300 times the number of proteins containing UAA, which can produce modified yeast. According to them, we are already talking about such quantities that can be used for the industrial production of proteins with UAA for therapeutic or research purposes. In total, the researchers managed to obtain proteins containing two different UAA – DanAla and OmeTyr.
Source: J. Am. Chem. Soc., 2008, 130, 6066; DOI: 10.1021/ja800894n