Metalâ Chelated Polymer Nanodiscs for NMR Studies

Paramagnetic relaxation enhancement (PRE) is commonly used to speed up spin lattice relaxation time (T1) for rapid data acquisition in NMR structural studies. Consequently, there is significant interest in novel paramagnetic labels for enhanced NMR studies on biomolecules. Herein, we report the synthesis and characterization of a modified poly(styreneâ coâ maleic acid) polymer which forms nanodiscs while showing the ability to chelate metal ions. Cu2+â chelated nanodiscs are demonstrated to reduce the T1 of protons for both polymer and lipidâ nanodisc components. The chelated nanodiscs also decrease the proton T1 values for a waterâ soluble DNA Gâ quadruplex. These results suggest that polymer nanodiscs functionalized with paramagnetic tags can be used to speedâ up data acquisition from lipid bilayer samples and also to provide structural information from waterâ soluble biomolecules.Speeding up data acquisition: Design of a polymer nanodisc containing a DOTA chelator enables the utilization of the PRE effect in studies using lipid nanodiscs. This new technique can be applied to waterâ soluble biomolecules such as Gâ quadruplexes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/1/anie201910118.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/2/anie201910118-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/3/anie201910118_am.pd

Metalâ Chelated Polymer Nanodiscs for NMR Studies

Paramagnetic relaxation enhancement (PRE) is commonly used to speed up spin lattice relaxation time (T1) for rapid data acquisition in NMR structural studies. Consequently, there is significant interest in novel paramagnetic labels for enhanced NMR studies on biomolecules. Herein, we report the synthesis and characterization of a modified poly(styreneâ coâ maleic acid) polymer which forms nanodiscs while showing the ability to chelate metal ions. Cu2+â chelated nanodiscs are demonstrated to reduce the T1 of protons for both polymer and lipidâ nanodisc components. The chelated nanodiscs also decrease the proton T1 values for a waterâ soluble DNA Gâ quadruplex. These results suggest that polymer nanodiscs functionalized with paramagnetic tags can be used to speedâ up data acquisition from lipid bilayer samples and also to provide structural information from waterâ soluble biomolecules.Speeding up data acquisition: Design of a polymer nanodisc containing a DOTA chelator enables the utilization of the PRE effect in studies using lipid nanodiscs. This new technique can be applied to waterâ soluble biomolecules such as Gâ quadruplexes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/1/anie201910118.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/2/anie201910118-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152508/3/anie201910118_am.pd

Structural polymorphism driven by a register shift in a CGAG-rich region found in the promoter of the neurodevelopmental regulator AUTS2 gene

The AUTS2 gene has been shown to influence brain development by controlling the number of neurons, promoting the growth of axons and dendrites and regulating neuronal migration. The expression of two isoforms of AUTS2 protein is precisely regulated and misregulation of their expression has been correlated with neurodevelopmental delay and autism spectrum disorder. A CGAG-rich region, which includes a putative protein binding site (PPBS), d(AGCGAAAGCACGAA), was found in the promoter region of AUTS2 gene. We show that oligonucleotides from this region adopt thermally stable non-canonical hairpin structures stabilized by G:C and sheared G:A base pairs arranged in a repeating structural motif we termed CGAG block. These motifs are formed consecutively, in a way that exploits a shift in register throughout the whole CGAG repeat to maximize the number of consecutive G:C and G:A base pairs. The differences in CGAG repeat shifting affect the structure of the loop region, where PPBS residues are predominantly located, specifically the loop length, types of base pairs and the pattern of base-base stacking. Finally, we propose a previously unexplored mechanism, by which different folds in the CGAG-rich region could cause a switch in expression between the full-length and C-terminal isoforms of AUTS2