The M. tuberculosis antigen 85 complex and mycolyltransferase activity

Lett Appl Microbiol. 2002;34(4):233-7. doi: 10.1046/j.1472-765x.2002.01091.x.


Aims: The antigen 85 complex (Ag85) from Mycobacterium tuberculosis consists of three abundantly secreted proteins (FbpA, FbpB and FbpC2) which play a key role in the pathogenesis of tuberculosis and also exhibit cell wall mycolyltransferase activity. A related protein with similarity to the Ag85 complex was recently annotated in the M. tuberculosis genome as FbpC1. An investigation was carried out to determine whether FbpC1 may also possess mycolyltransferase activity, a characteristic feature of the Ag85 complex.

Methods and results: Heterologous expression of FbpA, FbpC1 and FbpC2 was performed in Escherichia coli. Recombinant proteins were purified under non-denaturating conditions and used in an in vitro mycolyltransferase assay.

Conclusions: In contrast to FbpA and FbpC2, recombinant FbpC1 did not possess in vitro mycolyltransferase activity and was not recognized by two monoclonal antibodies to the native Ag85.

Significance and impact of the study: Mycolyltransferase activity is restricted to FbpA, FbpbB and FbpC2 only; the actual function of FbpC1 remains to be established.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases / metabolism*
  • Amino Acid Sequence
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / isolation & purification
  • Antigens, Bacterial / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Molecular Sequence Data
  • Multienzyme Complexes / chemistry
  • Mycobacterium tuberculosis / enzymology*
  • Mycobacterium tuberculosis / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Sequence Analysis, Protein


  • Antigens, Bacterial
  • Bacterial Proteins
  • Multienzyme Complexes
  • Recombinant Proteins
  • antigen 85C1, Mycobacterium tuberculosis
  • antigen 85C2, Mycobacterium tuberculosis
  • Acyltransferases
  • antigen 85A, Mycobacterium tuberculosis
  • antigen 85B, Mycobacterium tuberculosis
  • antigen 85C, Mycobacterium tuberculosis
  • trehalose mycolyltransferase