The M. tuberculosis antigen 85 complex and mycolyltransferase activity

• DOI: 10.1046/j.1472-765x.2002.01091.x
• Publication Date: 2003-03-12T10:16:22Z
• Authors: L. Kremer; W.N. Maughan; R.A. Wilson; L.G. Dover; G.S. Besra
• Keywords: 0301 basic medicine; Antigens, Bacterial; Molecular Sequence Data; Mycobacterium tuberculosis; Recombinant Proteins; 3. Good health; 03 medical and health sciences; Bacterial Proteins; Multienzyme Complexes; Sequence Analysis, Protein; Amino Acid Sequence; Sequence Alignment; Acyltransferases

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