Product of the month: February

4-Azido-L-homoalanine

Recombinant Incorporation of Amino Acids into Proteins:

Mutant or modified aminoacyl-tRNA synthetases (aaRS) have been used to charge non-natural amino acids to the corresponding tRNA, which incorporates them into polypeptides or proteins during recombinant synthesis. As azido homoalanine (Aha) is a structure analogue of methionine (Met), Met has been replaced effectively by Aha in proteins by the native methionyl tRNA synthetase of E. coli, [1]. A modified yeast phenylalanyl-tRNA synthetase was prepared by introduction of a T415G or T415A mutation in its α-subunit; specific residues in tryptophanyl-tRNA synthetase and methionyl-tRNA synthetase are also identified, where mutagenesis results in specificity for non-natural aminoacyl-tRNA molecules. Further developments and inventions have been done to specifically incorporate a vast number of Click components into practically any protein.

Once the azido function has been built into the protein sequence, conjugation with a large number of diverse partners including PEG-polymers, dyes, cofactors, antibodies, small molecules, toxins, additional proteins and peptides opens a wide field with many different applications from therapeutics to diagnostics.

For Incorporation of Aha by Chemical Synthesis into Peptides or other Organic Molecules the following Building Blocks are available:

• BAA1800 Boc-L-Aha-OH*CHA CAS: 120042-08-2net
• BAA1805 Boc-D-Aha-OH*CHA
• FAA6620 Fmoc-L-Aha-OH CAS: 942518-20-9
• FAA6810 Fmoc-D-Aha-OH
• ZAA5700 Z-L-Aha-OH*DCHA

References:

• K. L. Kiick, E. Saxon, D. A. Tirrell, C. R. Bertozzi, Proc. Natl. Acad. Sci. USA 2002; 99: 19.
• Patent: WO 2007103307
• High-Throughput Screening for Methionyl-tRNA Synthetases That Enable Residue-Specific Incorporation of Noncanonical Amino Acids into Recombinant Proteins in Bacterial Cells; Tae Hyeon Yoo and David A. Tirrell; Angew. Chem. Int. Ed. 2007; 46: 5340 –5343; DOI: 10.1002/anie.200700779.