Genome complexity: DNA's physical properties (Introduction)

by David Turell , Tuesday, March 09, 2021, 20:04 (1144 days ago) @ David Turell

Under amazingly designed controls:

https://physicsworld.com/a/make-or-break-building-soft-materials-with-dna/

"DNA molecules are constantly getting broken up and glued back together again with a new topology (figure 2). But there’s one big difference: the DNA needs to preserve its genetic sequence otherwise cells might die or diseases could be triggered.

***

"Nature requires proteins to perform topological operations on DNA while maintaining the original information (the DNA sequence) intact.

"This has a fundamental impact on how topological operations are performed on DNA. Unlike worm-like micelles – where the operations can occur at random anywhere along the micelle and at any time – the topological changes on DNA have to happen at the right place and the right time (they have to be “regulated” as biologists love to say).

***

"To break DNA, for example, you need “restriction enzymes”, which cut the chain only where a certain DNA sequence is recognized. Topoisomerase proteins, meanwhile, have to be precisely positioned at certain locations on chromosomes where entanglements and mechanical stress often accumulate. Similarly, when two pieces of DNA reconnect and recombine – for example when parental genetic material is shuffled in gametes (the precursor of egg and sperm cells) – the process is tightly regulated in space and time to avoid aberrant chromosomes in cells. It’s almost as if DNA (thanks to proteins) is a smart worm-like micelle."

Comment: To do this type of research the author must use enzymes that are used by life's processes. He cannot just step in on his own and invent new chemistry. He is dealing with designed molecules that have electrochemical properties, which by design produce very specific results. However by learning how to manipulate DNA with the proper enzymes, he can produce artificial DNA with new properties. Using CRISPR to slice and dice DNA is one current example.