In what is believed to be a first for chemical biology, Dr. Wenshe Liu, an assistant professor of chemistry at Texas A&M University, and his research team have uncovered a way to successfully incorporate two different noncanonical amino acids into a single protein in Escherichia coli bacteria.

E. coli, commonly found in the lower intestine of warm-blooded organisms, encompasses many strains, most of which are harmless. However, some can cause serious food poisoning in humans and are occasionally responsible for costly product recalls.

Previously, Liu says, it had only been possible to introduce a single new amino acid into a protein, the genetic code of which includes information for only 20 amino acids. Now, such a finding, first reported in the prestigious international journal Angewandte Chemie, could have tremendous implications for science, technology and medicine.

For example, bacteria could soon be genetically engineered to produce proteins that have been modified with various characteristics of interest for researchers.

"All proteins are made up of 20 amino acids which are genetically coded," Liu says. "The work we have done was to devise a method to significantly expand the amino acid inventory of proteins and synthesize proteins made up of 22 different kinds of amino acids."

In normal protein synthesis, tRNA transports the amino acid to the place where protein synthesis occurs at the best of codons that signal when to start and stop. Three "stop codons" naturally exist to code protein translation termination. By mutating two unique tRNAs to recognize two different stop codons, mutations in their associated aminoacyl tRNA synthetases occur that allow for the introduction of two synthetic amino acids to the tRNAs. Liu and his colleagues then incorporated the altered genetic material into the bacterial cells, which then assimilate two noncanonical amino acids into one protein.

"This work has far-reaching potential with applications in basic research, medicine and industry," Liu explains.

Liu's research, which involves several additional Texas A&M chemists, was funded in part by the Texas A&M Department of Chemistry and a grant from the Houston-based Welch Foundation, one of the United States' oldest and largest private funding sources for basic chemical research.

To read the paper or learn more about Angewandte Chemie, go to http://www.wiley-vch.de/publish/en/journals/bySubjectCH00/2001/news/13376/?sID=652op8h709icb7vr27c9369f63.

For more information Liu's research, visit http://www.chem.tamu.edu/rgroup/liu/index.html.


Contact: Chris Jarvis, (979) 845-7246 or cjarvis@science.tamu.edu or Dr. Wenshe Liu, (979) 845-1746 or wliu@chem.tamu.edu

Jarvis Chris

  • Dr. Wenshe Liu

  • An expanded genetic code

    Dr. Wenshe Liu and his research team have successfully introduced two different noncanonical amino acids into E. coli bacteria, a first in chemical biology that offers big implications in basic research, industry and medicine.

© Texas A&M University. To request use of any of our photographs for educational use or to view additional options from our archive, please contact the College of Science Communications Office.

College of Science
517 Blocker
TAMU 3257 | 979-845-7361
Site Policies
Contact Webmaster
Social Media