Washington, June 12 (ANI): A team of scientists has created a simple chemical system that mimics DNA

June 12th, 2009 - 2:48 pm ICT by ANI  

Washington, June 12 (ANI): A team of scientists has created a simple chemical system that mimics DNA, which could offer possible clues about the primordial world, and how life emerges.

The new analog to DNA, created by a team of Scripps Research scientists, assembles and disassembles itself without the need for enzymes.

Because the new system comprises components that might reasonably be expected in a primordial world, the new chemical system could answer questions about how life could emerge.

The work might also be a starting point on the way to exotic new materials that repair themselves or transform in response to their environment.

While much of the past work with DNA analogs such as PNA (Peptide nucleic acid) has focused on nucleobases already anchored to their backbone units, Professor Reza Ghadiri, a Scripps Research chemist and team leader of the new research, had the idea of working with simpler building blocks.

If these blocks had easily reversed bonds, unlike DNA and PNA, it could avoid the need for enzymes while preserving key characteristics for encoding information.

The resulting new system involves two main component types.

The backbone units are peptides linked in a set pattern with the amino acid cysteine exposed and available to react.

These peptides interact with the same nucleobases found in DNA, but each nucleobase is bound to an organic compound known as a thioester.

If an unzipped segment of DNA is added as a template to a solution with the tPNA components, the nucelobase soldiers will automatically assume a formation on peptide strands that complements the DNA according to standard Watson-Crick pairing of adenine with thymine and cytosine with guanine.

The complementary tPNA and DNA strands bond, but these pairings can then be unzipped by adding to the mix complementary DNA strands, which outcompete the tPNA for space on the initial templates.

The DNA-DNA pairings remain stable, causing the tPNA components to resume their unstable shuffling until a new DNA template is added and the process begins again.

The Ghadiri team was also able to show that a strand of tPNA can act as a template, causing complementary tPNA formation and strand pairing, though they have not yet achieved self-replication for tPNA, an ultimate goal.

All of the chemical constituents of the assembled tPNA could have been found in a world before life began.

“So, it is tantalizing to think about the possibility of peptides and nucleic acids involved in primordial genetic systems,” said Ghadiri. (ANI)

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