The Transportome of the Human Mucosal Pathogen Ureaplasma urealyticum
Lethbridge Undergraduate Research Journal
Ureaplasma urealyticum has been one of the most prominent mucosal pathogens having many tropisms in humans. This pathogen is most notable for its high gene density in its genome i.e. the genes, more than 600, encode almost 95% of the genome, which is suggestive of the fact that it has dispensed with many regulatory and biosynthetic genes for many metabolites and nutrients. By evolution, transporters have either substituted other genes or have duplicated themselves into paralogous members in Ureaplasma. SwissProt analysis and Transporter classification database were used to identify 67 open reading frames which represented the transporter dataset proteins from the whole genome. By this method, we identified a total of 20 transporters for haeme and/or iron (inclusive of binding and membrane subunits), 7 for inorganic cations (3 for Co2+, and one each for Mg2+, Cu2+, Ca2+ and K+), 11 for protons/ions, 5 for oligopeptides, 2 for amino acids, 2 for ammonium generated by urea hydrolysis, 4 for spermidine-putrescine, 4 for inorganic phosphate, 4 for sugars, and 2 belonging to the MOP (Multidrug-Oligosaccharidyl-lipid- Polysaccharide Flippase Superfamily) MATE (Mullti drug and Toxin Extrusion) class of membrane proteins. In addition, there are 6 other transporters, among which 5 belong to the ABC transporter family which translocate unidentified substrates. Two groups of paralogous iron transporters were identified by phylogenetic analysis using PHYLIP. Conserved residues and domains in individual transporter families were obtained by using Pro Dom and Pfam databases. In order to incorporate the missing transporters of Ureaplasma urealyticum in our work, we have also included the studies relating to the possibility of finding transmembrane-signature bearing proteins from among the hypothetical proteins. With this end in sight, we have utilized 5 different tools (TMHMM, SOSUI, HMMTOP, TopPred, and waveTM) to estimate the probable transporter proteins. Each of these tools follows completely different algorithms. Since these tools are prone to errors mainly as a result of false predictions of signal peptides as transmembrane segments, we have utilized an additional tool: SignalP, which provides to exclude the signal peptide-bearing proteins from the dataset. Transportome based studies of mucosal pathogens can give rise to many new drug and vaccine targets for prophylactic and therapeutic interventions.
Mucous membrane , Pathogenic microorganism
Sudhakar, P., Subramani, P. (2007). The Transportome of the Human Mucosal Pathogen Ureaplasma urealyticum. Lethbridge Undergraduate Research Journal, 2(1).