2B2I:
reference: Crystal structure of the archaeal ammonium transporter Amt-1 from Archaeoglobus fulgidus., Andrade SL, Dickmanns A, Ficner R, Einsle O, Proc Natl Acad Sci U S A. 2005 Oct 18;102(42):14994-9. Epub 2005 Oct 7. PMID: 16214888

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).