Studying the Conformation of a Silaffin-Derived Pentalysine Peptide Embedded in Bioinspired Silica using Solution and Dynamic Nuclear Polarization Magic-Angle Spinning NMR

Smart materials are created in nature at interfaces between biomolecules and solid materials. The ability to probe the structure of functional peptides that engineer biogenic materials at this heterogeneous setting can be facilitated tremendously by use of DNP-enhanced solid-state NMR spectroscopy. This sensitive NMR technique allows simple and quick measurements, often without the need for isotope enrichment. Here, it is used to characterize a pentalysine peptide, derived from a diatom’s silaffin protein. The peptide accelerates the formation of bioinspired silica and gets embedded inside the material as it is formed. Two-dimensional DNP MAS NMR of the silica-bound peptide and solution NMR of the free peptide are used to derive its secondary structure in the two states and to pinpoint some subtle conformational changes that the peptide undergoes in order to adapt to the silica environment. In addition, interactions between abundant lysine residues and silica surface are identified, and proximity of other side chains to silica and to neighboring peptide molecules is discussed

Resolución 0020. Por medio de la cual se modifica la resolución 013 de 28 de noviembre de 2019 que establece la conformación del equipo institucional saber pro

We investigate the combined effect of perdeuteration and fast magic-angle spinning on the resolution and sensitivity of proton-detected protein NMR spectra and on coherence lifetimes. With 60 kHz spinning of a microcrystalline α-spectrin SH3 sample at a field strength of 23 T, a regime is attained where there is no substantial difference in resolution between perdeuterated samples with 10 or 100% protons at the exchangeable sites.¹H resolution is then limited by inhomogeneous contributions. Upon fast spinning, the most dramatic line narrowing effects are observed for residues in the loop or bend regions of the protein, probably due to the removal of destructive dynamics effects. This investigation paves the way for using samples with 100% protons at the exchangeable sites in structure determination protocols, since all backbone amide sites can now contribute to the signal