This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mitchell, A. Articles by Finch, L. R. Search for Related Content PubMed PubMed Citation Articles by Mitchell, A. Articles by Finch, L. R.

 Previous Article  |  Next Article 

J Bacteriol. 1977 June; 130(3): 1047-1054
Copyright © 1977 American Society for Microbiology. All Rights Reserved.

Pathways of Nucleotide Biosynthesis in Mycoplasma mycoides subsp. mycoides

Russell Grimwade School of Biochemistry, University of Melbourne, Parkville, Victoria 3052, Australia

ABSTRACT

By measuring the specific activity of nucleotides isolated from ribonucleic acid after the incorporation of ¹⁴C-labeled precursors under various conditions of growth, we have defined the major pathways of ribonucleotide synthesis in Mycoplasma mycoides subsp. mycoides. M. mycoides did not possess pathways for the de novo synthesis of nucleotides but was capable of interconversion of nucleotides. Thus, uracil provided the requirement for both pyrimidine ribonucleotides. Thymine is also required, suggesting that the methylation step is unavailable. No use was made of cytosine. Uridine was rapidly degraded to uracil. Cytidine competed effectively with uracil to provide most of the cytidine nucleotide and also provided an appreciable proportion of uridine nucleotide. In keeping with these results, there was a slow deamination of cytidine to uridine with further degradation to uracil in cultures of M. mycoides. Guanine was capable of meeting the full requirement of the organism for purine nucleotide, presumably by conversion of guanosine 5'-monophosphate to adenosine 5'-monophosphate via the intermediate inosine 5'-monophosphate. When available with guanine, adenine effectively gave a complete provision of adenine nucleotide, whereas hypoxanthine gave a partial provision. Neither adenine nor hypoxanthine was able to act as a precursor for the synthesis of guanine nucleotide. Exogenous guanosine, inosine, and adenosine underwent rapid cleavage to the corresponding bases and so show a pattern of utilization similar to that of the latter.

This article has been cited by other articles:

• Schmidt, J. A., Browning, G. F., Markham, P. F. (2007). Mycoplasma hyopneumoniae mhp379 Is a Ca2+-Dependent, Sugar-Nonspecific Exonuclease Exposed on the Cell Surface. J. Bacteriol. 189: 3414-3424 [Abstract] [Full Text]