Understanding the interaction of Lipoarabinomannan with membrane mimetic architectures - 02/02/12
, Dominique N. Price a, Matthew Goertz b, Ramakrishnan Parthasarathi e, Gabriel A. Montaño c, Sandeep Kumar a, Matthew R. Scholfield a, Aaron S. Anderson a, S. Gnanakaran e, Srinivas Iyer d, Jurgen Schmidt a, Basil I. Swanson a, ⁎ 
Corresponding author. MS J567, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. Tel.: +1 505 606 2122; fax: +1 505 667 0440.Corresponding author. MS J515, C-DO, Los Alamos National Laboratory, Los Alamos, New NM 87545, USA. Tel.: +1 505 667 5814; fax: +1 505 665 4355.Summary |
Lipoarabinomannan (LAM) is a critical virulence factor in the pathogenesis of Mycobacterium tuberculosis, the causative agent of tuberculosis. LAM is secreted in urine and serum from infected patients and is being studied as a potential diagnostic indicator for the disease. Herein, we present a novel ultra-sensitive and specific detection strategy for monomeric LAM based on its amphiphilic nature and consequent interaction with supported lipid bilayers. Our strategy involves the capture of LAM on waveguides functionalized with membrane mimetic architectures, followed by detection with a fluorescently labeled polyclonal antibody. This approach offers ultra-sensitive detection of lipoarabinomannan (10 fM, within 15 min) and may be extended to other amphiphilic markers. We also show that chemical deacylation of LAM completely abrogates its association with the supported lipid bilayers. The loss of signal using the waveguide assay for deacylated LAM, as well as atomic force microscopy (AFM) images that show no change in height upon addition of deacylated LAM support this hypothesis. Mass spectrometry of chemically deacylated LAM indicates the presence of LAM-specific carbohydrate chains, which maintain antigenicity in immunoassays. Further, we have developed the first three-dimensional structural model of mannose-capped LAM that provides insights into the orientation of LAM on supported lipid bilayers.
Le texte complet de cet article est disponible en PDF.Keywords : Lipoarabinomannan, Amphiphiles, Diagnostics, Supported lipid bilayers, Biosensor, LAM atomistic model, Atomic force microscopy, Mass spectrometry
Plan
Vol 92 - N° 1
P. 38-47 - janvier 2012 Retour au numéro
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