Project description:Mycobacterium phlei, a nontuberculosis mycobacterial species, was first described in 1898-1899. We present the complete genome sequence for theM. phlei CCUG21000(T)type strain and the draft genomes for four additional strains. The genome size for all five is 5.3 Mb with 69.4% Guanine-Cytosine content. This is ?0.35 Mbp smaller than the previously reported M. phlei RIVM draft genome. The size difference is attributed partly to large bacteriophage sequence fragments in theM. phlei RIVM genome. Comparative analysis revealed the following: 1) A CRISPR system similar to Type 1E (cas3) in M. phlei RIVM; 2) genes involved in polyamine metabolism and transport (potAD,potF) that are absent in other mycobacteria, and 3) strain-specific variations in the number of ?-factor genes. Moreover,M. phlei has as many as 82 mce(mammalian cell entry) homologs and many of the horizontally acquired genes in M. phlei are present in other environmental bacteria including mycobacteria that share similar habitat. Phylogenetic analysis based on 693 Mycobacterium core genes present in all complete mycobacterial genomes suggested that its closest neighbor is Mycobacterium smegmatis JS623 and Mycobacterium rhodesiae NBB3, while it is more distant toM. smegmatis mc2 155.
Project description:The dihydrofolate reductase from Mycobacterium phlei was purified and characterized; it has an Mr of 15 000 and a pI of 4.8. It is competitively inhibited by both methotrexate and trimethoprim, although the affinity is less than for other bacterial dihydrofolate reductases.
Project description:YHS-domains are small protein modules which have been proposed to bind transition-metal ions like the related TRASH-domains. They are found in a variety of enzymes including copper-transporting ATPases and adenylyl cyclases. Here we investigate a class IIIc adenylyl cyclase from Mycobacterium phlei which contains a C-terminal YHS-domain linked to the catalytic domain by a peptide of 8 amino acids. We expressed the isolated catalytic domain and the full-length enzyme in E. coli. The catalytic domain requires millimolar Mn2+ as a cofactor for efficient production of cAMP, is unaffected by low micromolar concentrations of Cu2+ and inhibited by concentrations higher than 10 ?M. The full-length enzyme also requires Mn2+ in the absence of an activator. However, 1-10 ?M Cu2+ stimulate the M. phlei adenylyl cyclase sixfold when assayed with Mn2+. With Mg2+ as the probable physiological cofactor of the adenylyl cyclase Cu2+ specifically switches the enzyme from an inactive to an active state. Other transition-metal ions do not elicit activity with Mg2+. We favor the view that the YHS-domain of M. phlei adenylyl cyclase acts as a sensor for copper ions and signals elevated levels of the transition-metal via cAMP. By analogy to TRASH-domains binding of Cu2+ probably occurs via one conserved aspartate and three conserved cysteine-residues in the YHS-domain.
Project description:In French Polynesia, respiratory tract clinical isolate M26, displayed unusual phenotype and contradictory phylogenetic affiliations, suggesting a hitherto unidentified rapidly-growing Mycobacterium species. The phenotype of strain M26 was further characterized and its genome sequenced. Strain M26 genome consists in a 5,732,017-bp circular chromosome with a G + C% of 67.54%, comprising 5,500 protein-coding genes and 52 RNA genes (including two copies of the 16 S rRNA gene). One region coding for a putative prophage was also predicted. An intriguing characteristic of strain M26's genome is the large number of genes encoding polyketide synthases and nonribosomal peptide synthases. Phylogenomic analysis showed that strain M26's genome is closest to the Mycobacterium phlei genome with a 76.6% average nucleotide identity. Comparative genomics of 33 Mycobacterium genomes yielded 361 genes unique to M26 strain which functional annotation revealed 84.21% of unknown function and 3.88% encoding lipid transport and metabolism; while 48.87% of genes absent in M26 strain have unknown function, 9.5% are implicated in transcription and 19% are implicated in transport and metabolism. Strain M26's unique phenotypic and genomic characteristics indicate it is representative of a new species named "Mycobacterium massilipolynesiensis". Looking for mycobacteria in remote areas allows for the discovery of new Mycobacterium species.