Not strictly medical news, but scientists from the Carnegie Mellon University have constructed peptide nucleic acid (PNA) duplexes that contained metal ions and ligands inserted in place of central nucleobase pairs. Their hope is to create three-dimensional nanosize structures that could function as miniature circuits for future electronic devices:
“DNA nanotechnology has led to the construction of sophisticated three-dimensional nanoarchitectures composed exclusively from nucleic acid strands. These structures can acquire a completely new set of magnetic and electrical properties if metal ions are incorporated in the nucleic acids at specific locations because the metal ions have unpaired electrons,” said Catalina Achim, assistant professor of chemistry at the Mellon College of Science. “Our goal is to harness the information storage ability of metalcontaining PNAs to build molecular-scale devices–tiny replicas of today’s electronic circuit components, such as wires, diodes and transistors.”
Normally, DNA occurs as the well-known double helix first proposed by James Watson and Francis Crick 50 years ago. Each strand of the helix consists of a backbone linked to nucleobases, which occupy the inside of the helix. Nucleobases of one strand bind only to specific nucleobases of a complementary strand, and the two strands wind around one another like a twisted ladder. Artificially manufactured PNAs incorporate nucleobases that are bound to a backbone chain of pseudo-amino acids, rather than the sugar-phosphate groups of DNA.
“In modifying our PNAs so that they are significantly more stable, we have discovered that the PNA strands don’t have to be fully complementary for a metal-containing PNA duplex to form. This is an important finding because it should permit us to use non-complementary parts of the PNA duplexes to construct larger structures, which are useful for material science applications,” said Achim.