Space-filled models showing the structural similarity of two mercuric S-conjugates with commonly occurring sulfur-containing amino acids. Structural similarity exists between methionine and the cysteine (Cys)-S-conjugate of methylmercury (CH3Hg-S-Cys), and between cystine and the Cys-S-conjugate of Hg2+ (Cys-S-Hg-S-Cys). The models were generated with MolPOV 2.0 and POV Ray 3.5. Atoms: O, red; N, blue; C, dark gray (small); H, light gray; S, yellow; Hg, dark gray (large).