Architecture of the flexible tail tube of bacteriophage SPP1

Abstract

Bacteriophage SPP1 is a double-stranded DNA virus of the Siphoviridae family that infects the bacterium Bacillus subtilis. This family of phages features a long, flexible, non-contractile tail that has been difficult to characterize structurally. Here, we present the atomic structure of the tail tube of phage SPP1. Our hybrid structure is based on the integration of structural restraints from solid-state nuclear magnetic resonance (NMR) and a density map from cryo-EM. We show that the tail tube protein gp17.1 organizes into hexameric rings that are stacked by flexible linker domains and, thus, form a hollow flexible tube with a negatively charged lumen suitable for the transport of DNA. Additionally, we assess the dynamics of the system by combining relaxation measurements with variances in density maps.

Synthesis, Characterization, and Nanodisc Formation of Non‐ionic Polymers**

“…Thus, the newly devel-oped non-ionic polymers would be useful to expand the applications of the nanodisc technology. [25][26][27][28][29][30][31] Further, the natural source of the inulin-based polymer backbone makes them a great candidate for further development of biocompatible polymers and will also find many applications in drug delivery and membrane protein structural biology.…”

“…The reported results demonstrate that: 1) the efficacy of membrane solubilization depends on the degree of substitution in the polymer, 2) various hydrophobic moieties can be used to functionalize inulin, 3) the inulin‐based nanodiscs are stable under different pH values and various concentrations of divalent metal ions, 4) the inulin‐based nanodiscs align magnetically in the presence of an external magnetic field, which can be utilized in structural studies of membrane proteins by NMR, and 5) the new polymers can be used for detergent‐free extraction and purification of membrane proteins irrespective of their charge. Thus, the newly developed non‐ionic polymers would be useful to expand the applications of the nanodisc technology [25–31] . Further, the natural source of the inulin‐based polymer backbone makes them a great candidate for further development of biocompatible polymers and will also find many applications in drug delivery and membrane protein structural biology.…”

Virus Structures and Dynamics by Magic-Angle Spinning NMR

“…MAS frequencies of at least 8-10 kHz are necessary for recording well-resolved spectra for 13 C, 15 N, and 31 P nuclei. While this range of frequencies is sufficient for basic biological MAS NMR experiments, in practice the faster the specimen is spun, the higher the resolution and the sensitivity for the same rotor diameter.…”

Synthesis, Characterization, and Nanodisc formation of Non-ionic Polymers

“…Thus, the newly developed non-ionic polymers would be useful to expand the applications of the nanodisc technology. [25][26][27][28][29][30][31] Further, the natural source of the inulin-based polymer backbone makes them a great candidate for further developments of biocompatible polymers and will also find many applications in drug delivery and membrane protein structural biology.…”