Recently, we noted that a veteran origin of life researcher suggested that ID folk (not that he was one) should point to the ribosome. A friend rites to say that ID folk should also look at topoisomerase.
It’s an essential molecule that untangles the knots in DNA and, our friend notes, it is needed long before a cell has enough information to replicate itself.
This article on the topic is paywalled:
Abstract: Type IIA topoisomerases control DNA supercoiling and disentangle chromosomes through a complex ATP-dependent strand-passage mechanism. Although a general framework exists for type IIA topoisomerase function, the architecture of the full-length enzyme has remained undefined. Here we present the structure of a fully catalytic Saccharomyces cerevisiae topoisomerase II homodimer complexed with DNA and a nonhydrolyzable ATP analog. The enzyme adopts a domain-swapped configuration wherein the ATPase domain of one protomer sits atop the nucleolytic region of its partner subunit. This organization produces an unexpected interaction between bound DNA and a conformational transducing element in the ATPase domain, which we show is critical for both DNA-stimulated ATP hydrolysis and global topoisomerase activity. Our data indicate that the ATPase domains pivot about each other to ensure unidirectional strand passage and that this state senses bound DNA to promote ATP turnover and enzyme reset.
Schmidt, B., Osheroff, N. & Berger, J. Structure of a topoisomerase II–DNA–nucleotide complex reveals a new control mechanism for ATPase activity. Nat Struct Mol Biol 19, 1147–1154 (2012). https://doi.org/10.1038/nsmb.2388
Update: A friend sends us more open access, moderately readable information on topoisomerases:
From 2008: The DNA cleavage reaction of topoisomerase II: wolf in sheep’s clothing.
From 2020: Reviewing the Modification, Interactions, and Regulation of the C-Terminal
Domain of Topoisomerase IIα as a Prospect for Future Therapeutic Targeting
See also: Origin of life specialist suggested that ID folk should focus on the ribosome. Harvard’s George Church: And if I were to be an intelligent design defender, that’s what I would focus on; how did the ribosome come to be?