Thematic Einstein Semester on
Geometric and Topological Structure of Materials
Summer Semester 2021
Speaker
Stephen Hyde (U Sydney)
Title
Knotting of single-stranded (ss) RNA?
Abstract
ssRNA in many viruses, including SARS-COVID-19, which is responsible for our current upheaval, is almost knotted. Its 'H-type pseudoknot' is a crucial functional feature, allowing encoding of multiple proteins in the virus from a single stretch of its RNA. Structural studies of (ss)RNA suggest that ssRNA is rarely, if ever, knotted. That result may be due to inherent bias in ssRNA structures known to date, or may be more generally valid. Given the increasing probability of knotting with string length or crossing number, that finding is a priori surprising. Does the secondary structure of ssRNA (determined by its nucleotide sequence and Watson-Crick pairing), prevent or encourage knotting in H-type folds? The answer seems to be the latter. More generally, provided the simplest embedding of a fold is statistically knotted (and it usually is), its secondary structure alone leads to a nonzero probability of a ssRNA knot.
Contact
tes-summer2021@math.tu-berlin.de