The base-pair sequence of DNA determines its biological function. As you say, this sequence determines what kinds of proteins get made, including their exact shape (and more broadly how they behave).
But TFA is talking about the conformation (shape) of the DNA strand itself, not the protein structures that the DNA strand is used to make.
In living organisms, the long DNA molecule always forms a double-helix, irrespective of the base-pair sequence within the DNA. DNA double helices do actually twist and wrap into larger-scale structures: specifically by wrapping around histones
, and then twisting into larger helices that eventually form chromosomes
. There are hints that the DNA sequence itself is actually important in controlling how this twisting/packing happens (with ongoing research about how (innapropriately-named) "junk DNA
" plays a crucial role). However, despite this influence between sequence and super-structure, DNA strands essentially are just forming double-helices at the lowest level: i.e. two complementary DNA strands are pairing up to make a really-long double-helix.
What TFA is talking about is a field called "DNA nanotechnology", where researchers synthesize non-natural DNA sequences. If cleverly designed, these sequences will, when they do their usual base-pairing, form a structure more complex than the traditional "really-long double-helix". The structures that are designed do not occur naturally. People have created some really complex structures, made entirely using DNA. Again, these are structures made out of DNA
(not structures that DNA generates). You can see some examples by searching for "DNA origami
". E.g. one of the famous structures was to create a nano-sized smiley face
; others have 3D geometric shapes
constructs, and all kinds of other things.
The 'trick' is to violate the assumptions of DNA base-pairing that occur in nature. In living cells, DNA sequences are created as two long complementary strands, which pair up with each other. The idea in DNA nanotechnology is to create an assortment of strands. None of the strands are perfectly complementary to each other, but 'sub-regions' of some strands are complementary to 'sub-regions' on other strands. As they start pairing-up with each other, this creates cross-connections between all the various strands. The end result (if your design is done correctly) is that the strands spontaneously form a ver well-defined 3D structure, with nanoscale precision. The advantage of this "self-assembly
" is that you get billions of copies of the intended structure forming spontaneously and rapidly. Very cool stuff.
This kind of thing has been ongoing since 2006 at least. TFA erroneously implies that this most recent publication invented the field. Actually, this most recent publication is some nice work about how the design process can be made more robust (and software-automated). So, it's a fine paper, but certainly not the first demonstration of artificial 3D DNA nano-objects.