Question

Description: Unnatural amino acid mutagenesis might be one of the most groundbreaking achievements in modern biochemistry. This process allows for the incorporation of amino acids not coded for by the body (one's different from the 20 amino acids you studied in this course). This process allows scientists to use amino acids with different functional groups not found in nature.

Instructions: You will investigate how unnatural amino acid mutagenesis works. Take time to examine what changes needed to be made to the tRNA to allow for an unnatural amino acid to be used instead of the native substrate. Also focus on what codons are used to recognize the modified tRNA. How many different codons are there that can be used? What are they called? Please cite any sources used in this discussion (should contain 5-10 sources). This paper should be around 1-3 pages and cover a good deal of detail on how this process works. If you would like to submit early, I would be more than happy to look over it and return it with some suggestions.

Answer 1

Integration of un-natural amino acid in the protein provide a method for variety of biological process like protein structure function relationship. As, natural amino acid require, the machinery for protein synthesis like aminoacyl-tRNA synthetase , codon , tRNA , these un-natural amino acid will too require these machinery for protein synthesis. The machinery required for the un-natural amino acid synthesis are called as orthogonal set. In the orthogonal set, aminoacyl-tRNA synthetase should only able to charge un-natural amino acid.

A unique codon is required for orthogonal set, to code for the unnatural amino acid. Mostly amber codon are used for specifying amino acid. A collection of tRNA mutants could made by randomizing specific nucleotides, and the modified tRNA is selected for protein synthesis. Products of unnatural amino acid having proteins are in the variety of several milligrams to tens of milligrams per liter of cell culture.

External type-3 Pol III promoter is required for protein synthesis.

Reference:

1. Qian Wang, Angela R. Parrish, and Lei Wang Expanding the Genetic Code for Biological Studies

Chem Biol. 2009 Mar 27; 16(3): 323–336.

2. Jason W Chin Reprogramming the genetic code EMBO J. 2011 Jun 15; 30(12): 2312–2324.