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Solution NMR structure of a quiet outer membrane protein G Nanopore (OmpG mutant: Delta-L6-D215)Solution NMR structure of a quiet outer membrane protein G Nanopore (OmpG mutant: Delta-L6-D215)
Structural highlights
Function[OMPG_ECOLI] Forms channels functionally larger than those of classical porins.[1] May act as a regulator of the RCS-phosphorelay signal transduction pathway.[2] Publication Abstract from PubMedInterest in nanopore technology has been growing due to nanopores' unique capabilities in small molecule sensing, measurement of protein folding, and low-cost DNA and RNA sequencing. The E. coli beta-barrel outer membrane protein OmpG is an excellent alternative to other protein nanopores because of its single polypeptide chain. However, the flexibility of its extracellular loops ultimately limits applications in traditional biosensing. We deleted several residues in and near loop 6 of OmpG. The dynamic structure of the new construct determined by NMR shows that loops 1, 2, 6, and 7 have reduced flexibilities compared to those of wild-type. Electrophysiological measurements show that the new design virtually eliminates flickering between open and closed states across a wide pH range. Modification of the pore lumen with a copper chelating moiety facilitates detection of small molecules. As proof of concept, we demonstrate concurrent single-molecule biosensing of glutamate and adenosine triphosphate. Quiet Outer Membrane Protein G (OmpG) Nanopore for Biosensing.,Sanganna Gari RR, Seelheim P, Liang B, Tamm LK ACS Sens. 2019 May 24;4(5):1230-1235. doi: 10.1021/acssensors.8b01645. Epub 2019 , Apr 25. PMID:30990011[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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