{"id":18717,"date":"2025-12-29T12:17:30","date_gmt":"2025-12-29T10:17:30","guid":{"rendered":"https:\/\/www.nanion.de\/?post_type=resource_library&#038;p=18717"},"modified":"2025-12-29T12:17:30","modified_gmt":"2025-12-29T10:17:30","slug":"2025-on-the-mechanism-of-k-transport-through-the-inter-subunit-tunnel-of-kdpfabc","status":"publish","type":"resource_library","link":"https:\/\/nanion.com\/zh-hans\/resource_library\/2025-on-the-mechanism-of-k-transport-through-the-inter-subunit-tunnel-of-kdpfabc\/","title":{"rendered":"2025 &#8211; On the mechanism of K+ transport through the inter-subunit tunnel of KdpFABC"},"content":{"rendered":"<p>KdpFABC is an ATP-dependent membrane complex that enables prokaryotes to maintain potassium homeostasis under potassium-limited conditions. It features a unique hybrid mechanism combining a channel-like selectivity filter in KdpA with the ATP-driven transport functionality of KdpB. A key unresolved question is whether K<sup>+<\/sup>\u00a0ions translocate through the inter-subunit tunnel as a queue of ions or individually within a hydrated environment. Using molecular dynamics simulations, metadynamics, anomalous X-ray scattering, and biochemical assays, we demonstrate that the tunnel is predominantly occupied by water molecules rather than multiple K<sup>+<\/sup>\u00a0ions. Our results identify only one stable intermediate binding site for K<sup>+<\/sup>\u00a0within the tunnel, apart from the canonical sites in KdpA and KdpB. Free energy calculations reveal a substantial barrier (\u223c22 kcal\/mol) at the KdpA\u2013KdpB interface, making spontaneous K<sup>+<\/sup>\u00a0translocation unlikely. Furthermore, mutagenesis and functional assays confirm previous findings that Phe232 at this interface plays a key role in coupling ATP hydrolysis to K<sup>+<\/sup>\u00a0transport. These findings challenge previous models containing a continuous wire of K<sup>+<\/sup>\u00a0ions through the tunnel and suggest the existence of an as-yet unidentified intermediate state or mechanistic detail that facilitates K<sup>+<\/sup>\u00a0movement into KdpB.<\/p>\n","protected":false},"featured_media":0,"template":"","products_tags":[36],"resource_type":[75],"application_areas":[53,108],"therapeutic_areas":[143],"target_categories":[60],"target_families":[],"targets":[],"resource_keyword":[],"class_list":["post-18717","resource_library","type-resource_library","status-publish","hentry","products_tags-surfe2r-n1","resource_type-publication","application_areas-assay-development-and-validation","application_areas-transporters","therapeutic_areas-assay-development-and-validation","target_categories-transporters"],"acf":[],"_links":{"self":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_library\/18717","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_library"}],"about":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/types\/resource_library"}],"wp:attachment":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/media?parent=18717"}],"wp:term":[{"taxonomy":"products_tags","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/products_tags?post=18717"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_type?post=18717"},{"taxonomy":"application_areas","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/application_areas?post=18717"},{"taxonomy":"therapeutic_areas","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/therapeutic_areas?post=18717"},{"taxonomy":"target_categories","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/target_categories?post=18717"},{"taxonomy":"target_families","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/target_families?post=18717"},{"taxonomy":"targets","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/targets?post=18717"},{"taxonomy":"resource_keyword","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_keyword?post=18717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}