title: Selection of RNA aptamers against the M. tuberculosis EsxG protein using surface plasmon resonance-based SELEX.
abstract: Tuberculosis (TB), which is caused by Mycobacterium tuberculosis, remains one of the most prevalent infectious diseases worldwide which causes high morbidity and mortality. However, there is still limited understanding of the physiological processes that allow M. tuberculosis to survive in its host environment. One of the challenges is the limited availability of molecular probes that can be used to study some of the complex systems in mycobacteria. One such system is the ESX-3 secretion system, a specialized type VII secretion (T7S) system. This system is essential for optimal growth of pathogenic mycobacteria in low iron environments similar to that encountered by mycobacteria in macrophages during infection. EsxG, a protein of unknown function, is both encoded within the ESX-3 locus and secreted by the ESX-3 system. There are currently no molecular probes with high affinity and specificity to the EsxG protein that can be used to study it. Here we demonstrate the use of surface plasmon resonance-based systematic evolution of ligands by exponential enrichment (SELEX) to identify two aptamers, G43 and G78 that bind EsxG with high affinities, KD of 8.04±1.90 nM and 78.85±9.40 nM, respectively. Moreover, these aptamers preferentially bind EsxG over its homologue EsxA. Availability of such probes enables biological investigation of the role of this protein in mycobacteria and its potential as a biomarker for TB diagnosis.
authors.affiliation: Emerging Health Technologies, Biosciences Unit, CSIR, P.O. Box 395, Pretoria 0001, Gauteng, South Africa; KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Nqobile A C
authors.initials: NA
authors.lastname: Ngubane
authors.affiliation: Emerging Health Technologies, Biosciences Unit, CSIR, P.O. Box 395, Pretoria 0001, Gauteng, South Africa.
authors.forename: Lionel
authors.initials: L
authors.lastname: Gresh
authors.affiliation: KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pym
authors.affiliation: Department of Immunology and Infectious Disease, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, United States.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Rubin
authors.affiliation: Emerging Health Technologies, Biosciences Unit, CSIR, P.O. Box 395, Pretoria 0001, Gauteng, South Africa; Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa. Electronic address: mkhati@csir.co.za.
authors.forename: Makobetsa
authors.initials: M
authors.lastname: Khati
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D052156:SELEX Aptamer Technique / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D052157:Aptamers, Nucleotide; D001426:Bacterial Proteins
keywords: Aptamer; EsxG; M. tuberculosis; SELEX