NMR sample optimization and backbone assignment of a stabilized neurotensin receptor.

G protein-coupled receptors (GPCRs) are involved in a multitude of cellular signaling cascades and consequently are a prominent target for pharmaceutical drugs. In the past decades, a growing number of high-resolution structures of GPCRs has been solved, providing unprecedented insights into their mode of action. However, knowledge on the dynamical nature of GPCRs is equally important for a better functional understanding, which can be obtained by NMR spectroscopy.

Probing the Conformation States of Neurotensin Receptor 1 Variants by NMR Site-Directed Methyl Labeling.

G protein-coupled receptors (GPCRs) are key players in mediating signal transduction across the cell membrane. However, due to their intrinsic instability, many GPCRs are not suitable for structural investigations. Various approaches have been developed in recent years to remedy this situation, ranging from the use of more native membrane mimetics to protein-stabilization methods.

NMR backbone and methyl resonance assignments of an inhibitory G-alpha subunit in complex with GDP.

G-proteins are essential switch points at the cell membrane that control downstream signaling by their ability to adopt an inactive, GDP-bound or an active, GTP-bound state. Among other exchange factors, G-protein coupled receptors (GPCRs) induce exchange of GDP to GTP and thus promote the active state of the G-protein. The nucleotide-binding α subunit of the G-protein undergoes major conformational changes upon nucleotide binding.

A Split-Intein-Based Method for the Efficient Production of Circularized Nanodiscs for Structural Studies of Membrane Proteins.

Phospholipid nanodiscs are a native-like membrane mimetic that is suitable for structural studies of membrane proteins. Although nanodiscs of different sizes exist for various structural applications, their thermal and long-term stability can vary considerably. Covalently circularized nanodiscs are a perfect tool to overcome these limitations.

Stabilization and structural analysis of a membrane-associated hIAPP aggregation intermediate.

Membrane-assisted amyloid formation is implicated in human diseases, and many of the aggregating species accelerate amyloid formation and induce cell death. While structures of membrane-associated intermediates would provide tremendous insights into the pathology and aid in the design of compounds to potentially treat the diseases, it has not been feasible to overcome the challenges posed by the cell membrane. Here, we use NMR experimental constraints to solve the structure of a type-2 diabetes related human islet amyloid polypeptide intermediate stabilized in nanodiscs.

Conformational dynamics of a G-protein α subunit is tightly regulated by nucleotide binding.

Heterotrimeric G proteins play a pivotal role in the signal-transduction pathways initiated by G-protein-coupled receptor (GPCR) activation. Agonist-receptor binding causes GDP-to-GTP exchange and dissociation of the Gα subunit from the heterotrimeric G protein, leading to downstream signaling. Here, we studied the internal mobility of a G-protein α subunit in its apo and nucleotide-bound forms and characterized their dynamical features at multiple time scales using solution NMR, small-angle X-ray scattering, and molecular dynamics simulations.