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Solution structure of AR55 in 50% HFIP
Structural highlights
FunctionAPJ_HUMAN Receptor for apelin coupled to G proteins that inhibit adenylate cyclase activity. Alternative coreceptor with CD4 for HIV-1 infection; may be involved in the development of AIDS dementia. Publication Abstract from PubMedDetergent micelles are frequently employed as membrane mimetics for solution-state membrane protein nuclear magnetic resonance spectroscopy. Here we compare topology, structure, ps-ns time-scale dynamics, and hydrodynamics of a model protein with one transmembrane (TM) segment (residues 1-55 of the apelin receptor, APJ, a G-protein-coupled receptor) in three distinct, commonly used micellar environments. In each environment, two solvent-protected helical segments connected by a solvent-exposed kink were observed. The break in helical character at the kink was maintained in a helix-stabilizing fluorinated alcohol environment, implying that this structural feature is inherent. Molecular dynamics simulations also substantiate favorable self-assembly of compact protein-micelle complexes with a more dynamic, solvent-exposed kink. Despite the observed similarity in TM segment behavior, micelle-dependent differences were clear in the structure, dynamics, and compactness of the 30-residue, extramembrane N-terminal tail of the protein. This would affect intermolecular interactions and, correspondingly, the functional state of the membrane protein. Preserved Transmembrane Segment Topology, Structure, and Dynamics in Disparate Micellar Environments.,Langelaan DN, Pandey A, Sarker M, Rainey JK J Phys Chem Lett. 2017 May 12:2381-2386. doi: 10.1021/acs.jpclett.7b00867. PMID:28492329[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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