Related Experiment Video
Updated: Aug 10, 2026

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization
Published on: April 3, 2014
Novel deoxynucleoside-phosphorylating enzymes in mycoplasmas: evidence for efficient utilization of deoxynucleosides
1Department of Veterinary Medical Chemistry, The Swedish University of Agricultural Sciences, The Biomedical Centre, SE-751 23 Uppsala, Sweden. liya.wang@vmk.slu.se
Abstract:
Mycoplasmas are unable to synthesize purine and pyrimidine bases de novo. Therefore, salvage of existing nucleosides and bases is essential for their survival. Four mycoplasma species were studied with regard to their ability to phosphorylate deoxynucleosides. High levels of thymidine kinase (TK), deoxycytidine kinase (dCK), deoxyguanosine kinase (dGK) and deoxyadenosine kinase (dAK) activities were detected in extracts from Mycoplasma pneumoniae, Mycoplasma mycoides subsp. mycoides SC (M. mymySC), Acholeplasma laidlawii (A. laidlawii) and Mycoplasma arginini (M. arginini). Nucleoside phosphotransferase activities were found at high levels in A. laidlawii and low levels in M. arginini. Pyrophosphate-dependent deoxynucleoside kinase activities were detected mainly in A. laidlawii and M. mymySC extracts. Two open reading frames were identified in the M. mymySC genome; one showed 25% sequence identity to human dGK and the other one had about 26% sequence identity to human TK1. The M. mymySC dGK-like enzyme was cloned, expressed in Escherichia coli and affinity-purified. This enzyme phosphorylated dAdo, dGuo and dCyd, and the highest catalytic rate was with dAdo as substrate. Therefore, we suggest that this enzyme should be named deoxyadenosine kinase. The physiological role of mycoplasma dAK and TK may be to support the unusually large dATP and dTTP pools required for replication of mycoplasma genomes.
Insights
Mycoplasmas lack the ability to create new nucleosides, relying instead on salvage pathways. This study identified key deoxynucleoside kinase enzymes in four mycoplasma species, crucial for their survival and genome replication.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Mycoplasmas are unique bacteria incapable of de novo purine and pyrimidine synthesis.
- They rely entirely on salvage pathways for nucleoside and base acquisition, making these enzymes critical for survival.
Purpose of the Study:
- To investigate the deoxynucleoside phosphorylation capabilities of four mycoplasma species.
- To identify and characterize the specific deoxynucleoside kinases involved in mycoplasma nucleoside salvage.
Main Methods:
- Enzyme activity assays were performed on extracts from Mycoplasma pneumoniae, Mycoplasma mycoides subsp. mycoides SC, Acholeplasma laidlawii, and Mycoplasma arginini.
- Genomic analysis of M. mycoides subsp. mycoides SC identified potential kinase genes.
- A dGK-like gene from M. mycoides subsp. mycoides SC was cloned, expressed, and purified for functional characterization.
Main Results:
- High activities of thymidine kinase (TK), deoxycytidine kinase (dCK), deoxyguanosine kinase (dGK), and deoxyadenosine kinase (dAK) were detected across the studied species.
- Nucleoside phosphotransferase and pyrophosphate-dependent deoxynucleoside kinase activities varied among species.
- The characterized M. mycoides subsp. mycoides SC enzyme showed highest activity with deoxyadenosine, suggesting it functions as a deoxyadenosine kinase.
Conclusions:
- Mycoplasmas possess a robust deoxynucleoside salvage system involving multiple kinase activities.
- The identified deoxyadenosine kinase in M. mycoides subsp. mycoides SC likely contributes to maintaining large dATP pools essential for genome replication.
- These findings highlight the importance of salvage pathways for mycoplasma viability and potential therapeutic targets.
More Related Videos
Related Concept Videos
Biosynthesis of Nucleic Acids
Inhibitors of Viral Protein Synthesis
Antiviral Nucleoside Inhibitors

