title: Structure-based Epitope Mapping of Mycobacterium tuberculosis Secretary Antigen MTC28.
abstract: Secretary proteins of Mycobacterium tuberculosis are key players of the mycobacterial infection pathway. MTC28 is a 28-kDa proline-rich secretary antigen of Mycobacterium tuberculosis and is only conserved in pathogenic strains of mycobacteria. Here we report the crystal structure of MTC28 at 2.8- and 2.15-Å resolutions for the structure-based epitope design. MTC28 shares a "mog1p"-fold consisting of seven antiparallel β strands stacked between α helices. Five probable epitopes have been located on a solvent-accessible flexible region by computational analysis of the structure of MTC28. Simultaneously, the protein is digested with trypsin and the resulting fragments are purified by HPLC. Such 10 purified peptide fragments are screened against sera from patients infected with pulmonary tuberculosis (PTB). Two of these 10 fragments, namely (127)ALDITLPMPPR(137) and (138)WTQVPDPNVPDAFVVIADR(156),are found to be major immunogenic epitopes that are localized on the outer surface of the protein molecule and are part of a single continuous epitope that have been predicted in silico Mutagenesis and antibody inhibition studies are in accordance with the results obtained from epitope mapping.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
authors.forename: Prasun
authors.initials: P
authors.lastname: Kundu
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
authors.forename: Rupam
authors.initials: R
authors.lastname: Biswas
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
authors.forename: Somnath
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden,; Röntgen-Ångström-Cluster, Karolinska Institutet Outstation, Centre for Structural Systems Biology, c/o DESY, D-22607 Hamburg, Germany,; European Molecular Biology Laboratory, Hamburg Unit, 22603 Hamburg, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Reinhard
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
authors.forename: Anirudha
authors.initials: A
authors.lastname: Dutta
authors.affiliation: Abteilung für Mikrobiologie und Biotechnologie, Biozentrum Klein Flottbek, Universität Hamburg, Ohnhorststraße18, 22609 Hamburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Mueller-Dieckmann
authors.affiliation: Macromolecular Crystallography (HZB-MX), Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany.
authors.forename: Manfred S
authors.initials: MS
authors.lastname: Weiss
authors.affiliation: Nil Ratan Sirkar Medical College and Hospital,138 AJC Bose Road, Sealdah, Raja Bazar, Kolkata, West Bengal 700014, India.
authors.forename: Nishit Kumar
authors.initials: NK
authors.lastname: Pal
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India,. Electronic address: amitk@hijli.iitkgp.ernet.in.
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Das
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D056004:Molecular Dynamics Simulation; D009169:Mycobacterium tuberculosis / Q000276:immunology; D011487:Protein Conformation
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C109454:MTC28 protein, Mycobacterium tuberculosis
keywords: Mycobacterium tuberculosis; antigen; crystal structure; epitope mapping; high-performance liquid chromatography (HPLC)