Identifcation of the Phosphorylated Residues in TveIF5A by Mass Spectrometry

The initiation factor elF5A in Trichomonas vaginalis （TvelF5A） is previously shown to undergo hypusination, phosphorylation and glycosylation. Three different pI isoforms of TvelF5A have been reported. The most acidic isoform （pI 5.2） corresponds to the precursor TvelF5A, whereas the mature TvelF5A appears to be the most basic isoform （pI 5.5）. In addition, the intermediary isoform （pI 5.3） is found only under polyamine-depleted conditions and restored with exogenous putrescine. We propose that differences in PI are due to phosphorylation of the TvelF5A isoforms. Here, we have identified phosphorylation sites using mass spectrometry. The mature TvelF5A contains four phosphorylated residues （$3, T55, T78 and T82）. Phosphorylation at $3 and T82 is also identified in the intermediary TvelF5A, while no phosphorylated residues are found in the precursor TvelF5A. It has been demonstrated that elF5A proteins from plants and yeast are phosphorylated by a casein kinase 2 （CK2）. Interestingly, a gene encoding a protein highly similar to CK2 （TvCK2） is found in T. vaginalis, which might be involved in the phosphorylation of TvelF5A in T. vaginalis.

Application of antigenic biomarkers for Mycobacterium tuberculosis

The study and characterization of biomolecules involved in the interaction between mycobacteria and their hosts are crucial to determine their roles in the invasion process and provide basic knowledge about the biology and pathogenesis of disease.Promising new biomarkers for diagnosis and immunotherapy have emerged recently.Mycobacterium is an ancient pathogen that has developed complex strategies for its persistence in the host and environment,likely based on the complexity of the network of interactions between the molecules involved in infection.Several biomarkers have received recent attention in the process of developing rapid and reliable detection techniques for tuberculosis.Among the most widely investigated antigens are CFP-10(10-kDa culture filtrate protein),ESAT-6(6-kD a early secretory antigenic target),Ag85 A,Ag85 B,CFP-7,and PPE18.Some of these antigens have been proposed as biomarkers to assess the key elements of the response to infection of both the pathogen and host.The design of novel and accurate diagnostic methods is essential for the control of tuberculosis worldwide.Presently,the diagnostic methods are based on the identification of molecules in the humoral response in infected individuals.Therefore,these tests depend on the capacity of the host to develop an immune response,which usually is heterogeneous.In the last 20 years,special attention has been given to the design of multiantigenic diagnostic methods to improve the levels of sensitivity and specificity.In this review,we summarize the state of the art in the study and use of mycobacterium biomolecules with the potential to support novel tuberculosis control strategies.