Purine and Pyrimidine Metabolism in Mollicutes Species

Abstract

We studied the purine enzyme activities in dialyzed cytoplasmic extracts from the following eight species, representing four genera, of Mollicutes: Mycoplasma pneumoniae FHT (T = type strain) and M129, Mycoplasma bovigenitalium PG-1lT, Mycoplasma hominis PG-21T and 1620, Mycoplasma genitalium G-37T, Mycoplasma hyopneumoniae JT, Ureaplasma urealyticum T960T, Spiroplasma citri Mar0c-R8A2~, and Anaeroplasma intermedium 5LA. In an investigation of purine nucleoside kinase activity we also included M . hominis 13408, 10144, 13428, 1612, 1184, and Botte. All of these Mollicutes species except U . urealyticum had purine phosphoribosyltransferase activity for adenine, hypoxanthine, and guanine; U . urealyticum had only adenine phosphoribosyltransferase activity. All of the organisms had nucleoside phosphorylase activity which used either ribose 1-phosphate or deoxyribose 1-phosphate and adenine, hypoxanthine, or guanine for the synthesis of nucleosides and adenosine, deoxyadenosine, guanosine, deoxyguanosine, inosine, or deoxyinosine in the reverse direction. All had 5'-nucleotidase activity for adenosine monophosphate, deoxyadenosine monophosphate, inosine monophosphate, or guanosine monophosphate. Only M. hominis 1620,13408,10144, and 13428, A. intermedium, and S . citri had pyrophosphate-dependent nucleoside kinase activity. Only S. citri had nucleoside kinase activity with adenosine triphosphate and deoxyguanosine. We studied pyrimidine enzyme activities in all of the Mollicutes species except M . hominis and M . bovigenitalium. All of the Mollicutes species assayed had thymidine, thymidylate, and deoxycytidine kinase and thymidine and uridine phosphorylase activities. All of the Mycoplasma spp. had deoxycytotidine monophosphate and cytidine-deoxycytidine deaminase activities. All of the Mycoplasma spp. and U . urealyticum lacked deoxyuridine triphosphatase activity. U . urealyticum lacked deoxycytidine monophosphate deaminase activity, but otherwise it resembled all of the Mycoplasma spp. A. intermedium and S . citri differed from each other and from Mycoplasma spp. and U . urealyticum in the patterns of pyrimidine enzyme activities. Pyrophosphate-dependent nucleoside kinase activity was the most variably detected activity. None of the Mycoplasma spp. except four of eight strains of M . hominis had this kinase activity. Likewise, U . urealyticum did not have the pyrophosphate-dependent nucleoside kinase activity; however, A. intermedium and S . citri did have this enzyme activity. The absence of deoxyuridine triphosphatase activity in all Mycoplasma spp. may be related to their proposed rapid evolution and the relative lack of conserved sequences in their 5s ribosomal ribonucleic acids.

Nucleoside-catabolizing Enzymes in Mycoplasma-infected Tumor Cell Cultures Compromise the Cytostatic Activity of the Anticancer Drug Gemcitabine

“…We confirmed pronounced mycoplasma-associated conversion of dFdC to dFdU when exposing the radiolabeled drug to the spent culture medium (containing free-living mycoplasmas) or tumor cell extracts (containing enzymes of adherent/ intracellular mycoplasmas) of mycoplasma-infected but not uninfected MCF-7 cells. Cyd deaminase activity has been described before in mycoplasma extracts (45) and a cytidine deaminase gene was annotated in the genome of several mycoplasmas, including M. hyorhinis (46).…”

Suspected Utility of Enzymes with Multiple Activities in the Small GenomeMycoplasmaSpecies: The Replacement of the Missing "Household" Nucleoside Diphosphate Kinase Gene and Activity by Glycolytic Kinases

“…capricolum Kid T ( T 5 type species; McElwain and Pollack et al, 1987;DeSantis et al, 1989), M. fermentans PG-18 T (Pollack et al, 1996b), M. genitalium G37 T (McElwain et al, 1988;DeSantis et al, 1989), and M. pneumoniae M129 (McElwain et al, 1988;DeSantis et al, 1989;Himmelreich et al, 1996) were grown as previously described. M. pneumoniae FH T was grown in suspension static culture in an Edward's-type medium designated SNEP (Pollack et al, 1996a).…”

Pyrophosphate-Dependent Enzymes in Walled Bacteria Phylogenetically Related to the Wall-Less Bacteria of the Class Mollicutes

“…PPi-dependent nucleoside kinase has been found in all three orders of the class Mollicutes (18,22), whereas the other three enzymes have been reported only among members of the orders Acholeplasmatales and Anaeroplasmatales (7,17; Petzel et al, in press; this study). The occurrence of multiple PP,-dependent enzymes among the members of the orders Acholeplasmatales and Anaeroplasmatales and the walled phylogenetic relatives and the reported lack of any PPi-dependent enzymes besides PP,-dependent nucleoside kinase among the members of the order Mycoplasmatales support the rRNA sequence analyses that suggest that the acholeplasmas and anaeroplasmas represent the first branch(es) from the walled group (31, 40).…”

“…Some members of the orders Mycoplasmatales and Acholeplasrnatales have activities for (deoxy)ribonucleoside kinases that are dependent on pyrophosphate (PP,) as a cofactor (18,38), and Acholeplasma spp. have PP,-dependent 6-phosphofructokinase (PP,-PFK) activity (7, 23).…”

“…Among the anaerobic mollicutes, both Anaeroplasma intermedium (18) and Asteroleplasma anaerobium (J. P. Petzel, M. C. McElwain, D. DeSantis, J. Manolukas, M. V. Williams, P. A. Hartman, M. J. Allison, and J. D. Pollack, Arch, Microbiol., in press) have activities for PP,-dependent nucleoside kinases. Anaeroplasma intermedium also has PP,-PFK activity, whereas Asteroleplasma anaerobium has activity for a third PP,-dependent enzyme, pyruvate ,orthophosphate dikinase (PPDK; Petzel et al, in press).…”