Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. - Santhosh Kannan Venkatesan; Kusumika Saha; Azmat Sohail; Walter Sandtner; Michael Freissmuth; Gerhard F. Ecker; Harald H. Sitte; Thomas Stockner (PLoS Comput. Biol., 2015)