Cytoplasmic Tail of gp41 (IMAGE) University of Alabama at Birmingham Caption The structures of three membrane-associated cytoplasmic tails of gp41 are shown in red and orange, from this illustration of the trimeric spike structure. The rest of this HIV-1 envelope protein, which is docked on a gray membrane, are the structures of gp120 and gp41, shown in green, and the transmembrane segment, shown in blue. Credit Jamil Saad Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.