Genome complexity: RNA folding (Introduction)

by David Turell , Monday, January 18, 2021, 22:51 (1191 days ago) @ David Turell

Now seen in videos, and it ties itself and then unties:

https://www.sciencedaily.com/releases/2021/01/210115115247.htm

"Using data from RNA-folding experiments, the researchers generated the first-ever data-driven movies of how RNA folds as it is made by cellular machinery. By watching their videos of this folding occur, the researchers discovered that RNA often folds in surprising, perhaps unintuitive ways, such as tying itself into knots.

***

"'Folding takes place in your body more than 10 quadrillion times a second," Lucks said. "It happens every single time a gene is expressed in a cell, yet we know so little about it. Our movies allow us to finally watch folding happen for the first time."

***

"Lucks and his collaborators used this strategy to model the folding of an RNA called SRP, an ancient RNA found in all kingdoms of life. The molecule is well-known for its signature hairpin shape. When watching the videos, the researchers discovered that the molecule ties itself into a knot and unties itself very quickly. Then it suddenly flips into the correct hairpin-like structure using an elegant folding pathway called toehold mediated strand displacement.

"'To the best of our knowledge, this has never been seen in nature," Lucks said. "We think the RNA has evolved to untie itself from knots because if knots persist, it can render the RNA nonfunctional. The structure is so essential to life that it had to evolve to find a way to get out of a knot.'"

Comment: I love the strange Darwinist discussion in bold. Folding and unfolding must have a reason and purpose. Why does it bother to form a knot in the first place, instead of directly forming?