2EZQ:
reference: Three-dimensional solution structure of the 44 kDa ectodomain of SIV gp41., Caffrey M, Cai M, Kaufman J, Stahl SJ, Wingfield PT, Covell DG, Gronenborn AM, Clore GM, EMBO J 1998 Aug 17;17(16):4572-84. PMID: 9707417

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