Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Measurements of translation initiation from all 64 codons in E. coli



Ariel H. Hecht, Jeff E. Glasgow, Paul Jaschke, Lukmaan Bawazer, Matthew S. Munson, Jennifer R. Cochran, Drew Endy, Marc L. Salit


Our understanding of translation represents a cornerstone of molecular biology and underpins our capacity to engineer living matter. For decades, the codon AUG and a few near-cognates (GUG, UUG) have been exclusively considered as “start codons” for translation in Escherichia coli. The remaining 61 codons, outside of a few very rare exceptions, are not thought to initiate translation. Here we present the first systematic exploration of the capacity of all codons to initiate translation in E. coli. We examined the potential of all 64 codons to initiate translation of superfolder GFP (sfGFP) from a high-copy vector, and of 12 codons to initiate translation of sfGFP from a low- copy vector or NanoLuc luciferase from low- and single-copy vectors. We detected protein synthesis above background from 46 codons for sfGFP, and from all 12 codons for NanoLuc. Translation from these non-canonical codons ranged from 0.01% to 2% of translation initiated by AUG.
Nucleic Acids Research


Hecht, A. , Glasgow, J. , Jaschke, P. , Bawazer, L. , Munson, M. , Cochran, J. , Endy, D. and Salit, M. (2017), Measurements of translation initiation from all 64 codons in E. coli, Nucleic Acids Research, [online], (Accessed July 22, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created February 21, 2017, Updated January 27, 2020