Crystallization of a potassium ion channel and X‐ray and neutron data collection

• Published in: Acta crystallographica. Section F, Structural biology communications Structural biology communications, 2019-06, Vol.75 (6), p.435-438
• Main Authors: Langan, Patricia S., Vandavasi, Venu Gopal, Sullivan, Brendan, Harp, Joel, Weiss, Kevin, Coates, Leighton
• Format: Article
• Language: English
• Subjects: Bacillus cereus - metabolism; Bacterial Proteins - chemistry; BASIC BIOLOGICAL SCIENCES; Crystallization; Crystallography; Crystallography, X-Ray; Data collection; Datasets; ion channel; Ion channels; Macromolecules; membrane protein; Membrane proteins; Models, Molecular; neutron diffraction; Neutrons; Potassium; Potassium channels; Potassium Channels - chemistry; Protein Conformation; Research Communications; Selectivity; Water chemistry; Water purification; X‐ray diffraction
• ISSN: 2053-230X; 2053-230X
• DOI: 10.1107/S2053230X19006630

The mechanism by which potassium ions are transported through ion channels is currently being investigated by several groups using many different techniques. Clarification of the location of water molecules during transport is central to understanding how these integral membrane proteins function. Neutrons have a unique sensitivity to both hydrogen and potassium, rendering neutron crystallography capable of distinguishing waters from K+ ions. Here, the collection of a complete neutron data set from a potassium ion channel to a resolution of 3.55 Å using the Macromolecular Neutron Diffractometer (MaNDi) is reported. A room‐temperature X‐ray data set was also collected from the same crystal to a resolution of 2.50 Å. Upon further refinement, these results will help to further clarify the ion/water population within the selectivity filter of potassium ion channels. The growth of a large crystal of a potassium ion channel, and neutron and X‐ray data collection from the crystal are described.