Gramicidin S. Molecular model of the antibiotic drug Gramicidin S (C60.H92.N12.O10), also known as Gramicidin Soviet. This drug, an example of a cyclodecapeptide, is effective against both Gram positive and Gram negative bacteria. It was discovered by Russian microbiologist Georgyi Gause and his wife Maria Brazhnikova in 1942. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).