ProGP51 (Alanine and proline-rich secreted protein Apa (50/55-kDa or 45 kDa MPT 32))

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ProGP ID ProGP51 (Alanine and proline-rich secreted protein Apa (50/55-kDa or 45 kDa MPT 32))
Validation Status Characterized
Organism Information
Organism NameMycobacterium tuberculosis H37Rv
Domain Bacteria
Classification Phylum : Actinobacteria
Class : Actinomycetia
Orders : Corynebacteriales
Family : Mycobacteriaceae
Genus : Mycobacterium
Species : tuberculosis
Strain : H37Rv
Taxonomic ID (NCBI) 1773
Genome Information
GenBank AL123456.3
EMBL BX842578
Organism Additional Information It is the causative agent of human tuberculosis. The pathogenesis is influenced by its lipoglycans and glycolipids (having a wide range of immunomodulatory activities), and a variety of its virulence factors and antigens.
Gene Information
Gene NameApa (Rv1860) or modD
NCBI Gene ID 885896
GenBank Gene Sequence NC_000962
Protein Information
Protein NameAlanine and proline-rich secreted protein Apa (50/55-kDa or 45 kDa MPT 32)
UniProtKB/SwissProt ID P9WIR7
NCBI RefSeq YP_177849.1
Sequence length 325 AA
Subcellular LocationSecreted
Function 1. Immunodominant antigen. Elicits potent DTH (delayed-type hypersensitivity) responses in living-BCG-immunized guinea pigs. Stimulation of peripheral blood mononuclear cells from PPD positive individuals with Apa induces a Th1 type lymphoproliferative response with expansion of both CD4+ and CD8+ cells and increased IFN-γ production.
2. In Mtb, mannosylated nApa is a potential adhesin and has a role in host cell attachment, entry, and immune evasion, it induces a strong delayed-type hypersensitivity (DTH) in immunized animals, elicits mostly a Th1 type of T-cell response in healthy humans; induces IFN-γ production from CD4+ and CD8+ cells. Also functions as an adhesin, binds to mouse macrophages via mannose residues.
Glycosylation Status
Glycosylation Type O- (Thr) linked
Experimentally Validated Glycosite(s) in Full Length Protein(Signal peptide: 1-39) T49, T57, T66, T316, T313,T315
Experimentally Validated Glycosite(s ) in Mature ProteinT10, T18, T27, T277
Sequence Around Glycosites (21 AA) ADPEPAPPVPTTAASPPSTAA
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Technique(s) used for Glycosylation DetectionSchiff's staining, peroxidase-conjugated concanavalin A (ConA)-binding
Technique(s) used for Glycosylated Residue(s) Detection N-terminal amino acid sequencing coupled with fast atom bombardment-mass spectrometry (FAB-MS), Edman degradation on a gas-phase sequencer, FAB-MS
Protein Glycosylation- Implication 1. The presence of the mannose residues on the Apa protein was essential for the antigenicity of the molecules in T-cell-dependent immune responses in vitro (proliferation assay) and in vivo (delayed type hypersensitivity or DTH reaction). The deglycosylated antigen was 10-fold less active than native molecules in eliciting DTH. Mannosylation of antigen leads to selective targeting and subsequent greater presentation by dendritic cells.
2. In Mtb, mannosylated nApa is a potential adhesin and has a role in host cell attachment, entry, and immune evasion.
Glycan Information
Glycan Annotation Linkage: αMan-Thr.
34.6% sugar detected.
α-D-Manp(1→2)α-D-Manp (mannobiose), α-D-Manp (single mannose), α-D-Manp(1→2)α-D-Manp(1→2)α-D-Manp (mannotriose) are present. T10 and T18 are glycosylated with mannobiose, T27 with single mannose, and T277 with either of the three. The majority of the antigen species bear six, seven, or eight mannose residues (22, 24, and 17%, respectively), while others three, four, or five mannoses (5, 9, and 14%, respectively). Alpha-D-Man, mannobiose, or mannotriose, Thr residues at positions 10 and 18 were substituted a-D-Manp(132)a-D-Manp, position 27 was substituted with a single a-D-Manp, Thr-277 was substituted with either a-D-Manp, a-D-Manp(132)a-D-Manp, or a-D-Manp(132)a-D-Manp (132)a-D-Manp.
Technique(s) used for Glycan Identification GC-MS of partially methylated alditol acetates obtained by trifluoro acetic acid (TFA) hydrolysis of permethylated oligoglycosyl alditols which are released by elimination of the glycopeptides.
Protein Glycosylation linked (PGL) gene(s)
OST Gene NameProtein O-mannosyltransferase
Characterized Accessory Gene(s)Polyprenol-phosphate-mannose (PPM) synthase, Ppm1, is present. A second type of Ppm synthase (Rv3779 gene product) exclusive to slow-growing mycobacteria, is a membrane glycosyltransferase. It mannosylates polyprenyl-phosphates directly from GDP-mannose.
Accessory Gene(s)Progt IDProGT10.1
Additional CommentSec-mediated translocation influences the O-mannosylation. Ppm1 does not discriminate between polyprenol substrates with variable chain lengths and saturation of the isoprene units.
Glycosylation sites have been found to be located within proline-rich domains (or Thr-rich sequences) near the N-terminus and the C-terminus.
In a cell-free assay, the M. smegmatis mannosyltransferase activity in membrane and cell wall fraction has been shown to catalyze transfer of radiolabeled mannose from GDP-[14C]mannose to peptide acceptors. The acceptors consisted of Thr-rich sequences from M. tuberculosis 45 kDa antigen (Ref. no. 3).
The 45/47 kDa antigen (Apa) has also been glycosylated in Streptomyces lividans. The 45- and 47-kDa represent two glycoforms of the antigen (Ref. no. 2).
Year of Identification1989
Year of Identification Month Wise1989.09.01
Year of Validation 1996
ReferenceScherman, H., Kaur, D., Pham, H., Škovierová, H., Jackson, M. and Brennan, P.J., 2009. Identification of a polyprenylphosphomannosyl synthase involved in the synthesis of mycobacterial mannosides. Journal of bacteriology, 191(21), pp.6769-6772.
Corresponding Author Patrick J Brennan
ContactDepartment of Microbiology, Colorado State University, Fort Collins, Colorado 80523-1682, USA.
ReferenceLara, M., Servín-González, L., Singh, M., Moreno, C., Cohen, I., Nimtz, M. and Espitia, C., 2004. Expression, secretion, and glycosylation of the 45-and 47-kDa glycoprotein of Mycobacterium tuberculosis in Streptomyces lividans. Applied and Environmental Microbiology, 70(2), pp.679-685.
Corresponding Author Clara Espitia
ContactDepartment of Immunology, Institute of Biomedical Research, National Autonomous University of Mexico, Mexico D.F., Mexico.
ReferenceCooper, H.N., Gurcha, S.S., Nigou, J., Brennan, P.J., Belisle, J.T., Besra, G.S. and Young, D., 2002. Characterization of mycobacterial protein glycosyltransferase activity using synthetic peptide acceptors in a cell-free assay. Glycobiology, 12(7), pp.427-434.
Corresponding Author Douglas Young
ContactCentre for Molecular Microbiology and Infection, Imperial College of Science, Technology and Medicine, South Kensington, London, SW7 2AZ, England.
ReferenceHorn, C., Namane, A., Pescher, P., Riviere, M., Romain, F., Puzo, G., Bârzu, O. and Marchal, G., 1999. Decreased capacity of recombinant 45/47-kDa molecules (Apa) of Mycobacterium tuberculosis to stimulate T lymphocyte responses related to changes in their mannosylation pattern. Journal of Biological Chemistry, 274(45), pp.32023-32030.
Corresponding Author Gilles Marchal
ContactDepartment of Pathophysiology of Infection, Pasteur Institute, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France.
ReferenceRomain, F., Horn, C., Pescher, P., Namane, A., Riviere, M., Puzo, G., Barzu, O. and Marchal, G., 1999. Deglycosylation of the 45/47-kilodalton antigen complex of Mycobacterium tuberculosis decreases its capacity to elicit in vivo or in vitro cellular immune responses. Infection and immunity, 67(11), pp.5567-5572.
Corresponding Author Gilles Marchal
ContactDepartment of Pathophysiology of Infection, Pasteur Institute, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France.
ReferenceDobos, K.M., Khoo, K.H., Swiderek, K.M., Brennan, P.J. and Belisle, J.T., 1996. Definition of the full extent of glycosylation of the 45-kilodalton glycoprotein of Mycobacterium tuberculosis. Journal of bacteriology, 178(9), pp.2498-2506.
Corresponding Author JOHN T. BELISLE
ContactDepartment of Microbiology, Colorado State University, Fort Collins 80523, USA.
ReferenceMehaffy, C., Belisle, J.T. and Dobos, K.M., 2019. Mycobacteria and their sweet proteins: An overview of protein glycosylation and lipoglycosylation in M. tuberculosis. Tuberculosis, 115, pp.1-13.
Corresponding Author Carolina Mehaffy
ContactDepartment of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus delivery, Fort Collins, CO, USA
ReferenceNandakumar, S., Kannanganat, S., Dobos, K.M., Lucas, M., Spencer, J.S., Fang, S., McDonald, M.A., Pohl, J., Birkness, K., Chamcha, V. and Ramirez, M.V., 2013. O-mannosylation of the Mycobacterium tuberculosis adhesin Apa is crucial for T cell antigenicity during infection but is expendable for protection. PLoS pathogens, 9(10), p.e1003705.
Corresponding Author Suraj B. Sable
ContactDivision of Tuberculosis Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Reference Espitia, C. and Mancilla, R. (1989) Identification, isolation and partial characterization of Mycobacterium tuberculosis glycoprotein antigens. Clin Exp Immunol, 77, 378-383. [PubMed: 2478323]
ContactDepartment of Immunology, National Autonomous University of Mexico, D.F