The Chemical Composition of the Nucleic Acids and Other Macromolecular Constituents of Mycoplasma mycoides var. capri

Abstract

Samples of deoxyribonucleic-acid (DNA), mi-crosomal ribonucleic-acid (RNA) and a neutral polysaccharide from M. mycoides var. capri were isolated and analyzed. The DNA was found to have an adenine + thymine/guanine + cytosine value of 3.04, and the RNA to have an adenine + uracil/guanine + cytosine value of 1.21. The amino-acid composition of the protein of the organism was also determined and found to be in close agreement with the values expected by extrapolating the curves obtained from the amino-acid contents of the protein of several bacteria having DNA''s with a wide range of adenine + thymine/guanine + cytosine values (Sueoka, 1961). The values were also in close agreement with those obtained for the protein of Tetrahymena puriformis, which has a DNA of similar base composition (A + T/G + C = 3.0). Two significant exceptions were noted: the value for proline was almost twice as large as would have been expected and a large amount of cysteine was found. The Mycoplasma organisms contained a very small amount of a neutral poly-saccharide in which only glucose was detected.