Engineered Bacteria Are Genetic Rebels

By Goho, A. | Science News, May 15, 2004 | Go to article overview
Save to active project

Engineered Bacteria Are Genetic Rebels

Goho, A., Science News

In an ongoing effort to push the limits of genetic engineering, researchers have created a bacterium that can incorporate artificial amino acids into its proteins and do so by breaking a fundamental rule of molecular biology.

Virtually all organisms build their life-sustaining proteins from a set of 20 amino acids, as encoded in an organism's DNA. The genetic code is represented by sequences of four types of nucleotides, designated by the letters A, T, G, and C. Those sequences are broken down into three-letter blocks called codons. The cell's molecular machinery translates each codon into an amino acid and strings those amino acids together to form proteins.

To create an organism capable of making proteins from amino acids beyond the basic set of 20, a team of researchers led by Peter Schultz at the Scripps Research Institute in La Jolla, Calif., decided to expand the genetic code. Instead of having a three-letter codon system, the researchers created a four-letter system.

That "opens the possibility of adding multiple unnatural amino acids to the genetic code," says Christopher Anderson, one of the Scripps members who developed the organism.

Previously, the Schultz lab tricked bacteria and yeast cells into translating a naturally occurring three-letter nonsense codon--one that normally has no associated amino acid--within the cells' genomes into one of several artificial amino acids (SN: 8/16/03, p. 102). Although that enabled the organisms to churn out proteins using one extra amino acid, moving beyond 21 amino acids in this way would require the addition of new, unique codons, says Anderson.

In this latest experiment, the researchers engineered the gene-to-protein translation machinery of Escherichia coil cells to recognize the four-letter genetic sequence AGGA and to assign the artificial amino acid L-homoglutamine to that codon.

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
Loading One moment ...
Project items
Cite this article

Cited article

Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited article

Engineered Bacteria Are Genetic Rebels


Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

While we understand printed pages are helpful to our users, this limitation is necessary to help protect our publishers' copyrighted material and prevent its unlawful distribution. We are sorry for any inconvenience.
Full screen

matching results for page

Cited passage

Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.

Are you sure you want to delete this highlight?