Cover Picture: Design of S‐Allylcysteine in Situ Production and Incorporation Based on a Novel Pyrrolysyl‐tRNA Synthetase Variant (ChemBioChem 1/2017)

Abstract

The cover picture shows a journey from garlic to genetic code engineering: In this issue, Budisa and co‐workers report in vivo‐specific protein olefination with S‐allylcysteine (Sac), which is naturally abundant in garlic. Alternatively, it can also be biosynthesized in situ by supplementing the amino acid metabolism of E. coli with allylmercaptan. Sac is recognized and activated by the novel and unique pyrrolysyl‐tRNA synthetase‐based enzyme S‐allylcysteinyl‐tRNA synthetase (SacRS), which is capable of specifically accepting a small, polar amino acid instead of the long and bulky aliphatic natural substrate. In this way, a biochemical pathway for the production of proteins containing S‐allylcysteine as a minimal tag or label for chemical protein modification has been established. More information can be found in the communication by S. Panke, N. Budisa et al. on page 85 in Issue 1, 2017 (DOI: 10.1002/cbic.201600537).

Enhancement of Activity and Thermostability of Keratinase From Pseudomonas aeruginosa CCTCC AB2013184 by Directed Evolution With Noncanonical Amino Acids

“…Several efforts have been made to achieve that advantage in this field. p-Amino-phenylalanine, 5-hydroxytryptophan, L-phosphothreonine, L-dihydroxyphenylalanine, and S-allyl-L-cysteine were successfully biosynthesized in E. coli using enzymatic or metabolic pathway engineering, and were directly incorporated into the proteins using genetic code expansion ( Exner et al, 2017 ; Zhang et al, 2017 ; Kim et al, 2018 ; Chen et al, 2020 ). The continuous progress in biochemistry, molecular biology, and synthetic biology will lead to the synthesis of an increasing number of ncAAs in engineered cells.…”