Multivalent forms of the ribonuclease H1 hybrid binding domain are high-affinity binders of RNA-DNA hybrids.

The hybrid binding domain (HBD) is a conserved fold present in ribonucleases H1 that selectively recognizes RNA-DNA hybrids, which are structures present in cellular R-loops and participate in diverse biological processes. We engineered multivalent HBD proteins to create high-affinity hybrid binders. Using EMSA- and SPR-based analyses, we showed that the triple-HBD protein exhibits a ~ 22 000-fold increase in hybrid affinity (K 370 pm) relative to the single HBD (K 8.

Global and local mechanical properties control endonuclease reactivity of a DNA origami nanostructure.

We used coarse-grained molecular dynamics simulations to characterize the global and local mechanical properties of a DNA origami triangle nanostructure. The structure presents two metastable conformations separated by a free energy barrier that is lowered upon omission of four specific DNA staples (defect). In contrast, only one stable conformation is present upon removing eight staples.

Binary control of enzymatic cleavage of DNA origami by structural antideterminants.

Controlling DNA nanostructure interaction with protein is essential in developing nanodevices with programmable function, reactivity, and stability for biological and medical applications. Here, we show that the sequence-specific action of restriction endonucleases towards sharp triangular or rectangular DNA origami exhibits a novel, binary 'on/off' behaviour, as canonical recognition sites are either essentially fully reactive, or strongly resistant to enzymatic cutting. Moreover, introduction of structural defects in the sharp triangle can activate an otherwise unreactive site, with a site-to-defect distance of ∼50 nm.

Polymorphic thymidylate synthase gene impacts on overall survival of patients with epithelial ovarian cancer after platinum-based chemotherapy.

Aim: High levels of TS have been associated with a worse clinical outcome in several cancers including epithelial ovarian cancer (EOC). The TS gene (TYMS) is highly polymorphic and has an effect on mRNA/protein expression.

Materials & Methods: Six TYMS polymorphisms were investigated for overall survival (OS) in 216 EOC patients: TYMS 1494ins/del, TSER (variable number of tandem repeats of 28 bp), TSER G>C, TYMS 1053C>T, TYMS IVS6-68C>T and TYMS 1122A>G.