6hdc

Crystal structure of the potassium channel MtTMEM175 T38A variant in complex with a Nanobody-MBP fusion protein

spinqualitylabelsall models 6hdc, resolution 3.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6hdc is a 2 chain structure with sequence from Escherichia coli K-12, Lama glama and Marivirga tractuosa DSM 4126. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.4Å Ligands: GLC, K, LMT Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MALE_ECOLI Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides. Publication Abstract from PubMed The TMEM175 family constitutes recently discovered K(+) channels that are important for autophagosome turnover and lysosomal pH regulation and are associated with the early onset of Parkinson Disease. TMEM175 channels lack a P-loop selectivity filter, a hallmark of all known K(+) channels, raising the question how selectivity is achieved. Here, we report the X-ray structure of a closed bacterial TMEM175 channel in complex with a nanobody fusion-protein disclosing bound K(+) ions. Our analysis revealed that a highly conserved layer of threonine residues in the pore conveys a basal K(+) selectivity. An additional layer comprising two serines in human TMEM175 increases selectivity further and renders this channel sensitive to 4-aminopyridine and Zn(2+). Our findings suggest that large hydrophobic side chains occlude the pore, forming a physical gate, and that channel opening by iris-like motions simultaneously relocates the gate and exposes the otherwise concealed selectivity filter to the pore lumen. Structural basis for ion selectivity in TMEM175 K(+) channels.,Brunner JD, Jakob RP, Schulze T, Neldner Y, Moroni A, Thiel G, Maier T, Schenck S Elife. 2020 Apr 8;9. pii: 53683. doi: 10.7554/eLife.53683. PMID:32267231 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Maltose-binding protein 3D structures

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