{"id":4705,"date":"2023-02-17T07:09:40","date_gmt":"2023-02-17T07:09:40","guid":{"rendered":"http:\/\/ionchanneltargets.com\/resource_library\/cardiomyocytes-positive-inotropic-effects-in-human-ipsc-derived-cardiomyocytes-can-be-triggered-through-a-flexible-pro-maturation-environment\/"},"modified":"2023-02-17T07:09:40","modified_gmt":"2023-02-17T07:09:40","slug":"2005-kinetics-of-charge-translocation-in-the-passive-downhill-uptake-mode-of-the-na-h-antiporter-nhaa-of-escherichia-coli","status":"publish","type":"resource_library","link":"https:\/\/nanion.com\/ja\/resource_library\/2005-kinetics-of-charge-translocation-in-the-passive-downhill-uptake-mode-of-the-na-h-antiporter-nhaa-of-escherichia-coli\/","title":{"rendered":"2005 &#8211; Kinetics of charge translocation in the passive downhill uptake mode of the Na<sup>+<\/sup>\/H+ antiporter NhaA of Escherichia coli"},"content":{"rendered":"<p>The Na<sup>+<\/sup>\/H+\u00a0antiporter NhaA is the main Na<sup>+<\/sup>\u00a0extrusion system in E. coli. Using direct current measurements combined with a solid supported membrane (SSM), we obtained electrical data of the function of NhaA purified and reconstituted in liposomes. These measurements demonstrate NhaA&#8217;s electrogenicity, its specificity for Li+\u00a0and Na<sup>+<\/sup>\u00a0and its pronounced pH dependence in the range pH 6.5-8.5. The mutant G338S, in contrast, presents a pH independent profile, as reported previously. A complete right-side-out orientation of the NhaA antiporter within the proteoliposomal membrane was determined using a NhaA-specific antibody based ELISA assay. This allowed for the first time the investigation of NhaA in the passive downhill uptake mode corresponding to the transport of Na<sup>+<\/sup>\u00a0from the periplasmic to the cytoplasmic side of the membrane. In this mode, the transporter has kinetic properties differing significantly from those of the previously investigated efflux mode. The apparent Km\u00a0values were 11 mM for Na<sup>+<\/sup>\u00a0and 7.3 mM for Li+\u00a0at basic pH and 180 mM for Na<sup>+<\/sup>\u00a0and 50 mM for Li+\u00a0at neutral pH. The data demonstrate that in the passive downhill uptake mode pH regulation of the carrier affects both apparent Km\u00a0as well as turnover (Vmax).<\/p>\n","protected":false},"featured_media":0,"template":"","products_tags":[36],"resource_type":[75],"application_areas":[108],"therapeutic_areas":[],"target_categories":[60],"target_families":[],"targets":[],"resource_keyword":[],"class_list":["post-4705","resource_library","type-resource_library","status-publish","hentry","products_tags-surfe2r-n1","resource_type-publication","application_areas-transporters","target_categories-transporters"],"acf":[],"_links":{"self":[{"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/resource_library\/4705","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/resource_library"}],"about":[{"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/types\/resource_library"}],"wp:attachment":[{"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/media?parent=4705"}],"wp:term":[{"taxonomy":"products_tags","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/products_tags?post=4705"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/resource_type?post=4705"},{"taxonomy":"application_areas","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/application_areas?post=4705"},{"taxonomy":"therapeutic_areas","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/therapeutic_areas?post=4705"},{"taxonomy":"target_categories","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/target_categories?post=4705"},{"taxonomy":"target_families","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/target_families?post=4705"},{"taxonomy":"targets","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/targets?post=4705"},{"taxonomy":"resource_keyword","embeddable":true,"href":"https:\/\/nanion.com\/ja\/wp-json\/wp\/v2\/resource_keyword?post=4705"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}