Understanding the interaction of Lipoarabinomannan with membrane mimetic architectures

Harshini Mukundan, Dominique N. Price, Matthew Goertz, Ramakrishnan Parthasarathi, Gabriel A. Montaño, Sandeep Kumar, Matthew R. Scholfield, Aaron S. Anderson, S. Gnanakaran, Srinivas Iyer, Jurgen Schmidt, Basil I. Swanson

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)38-47
Number of pages10
JournalTuberculosis
Volume92
Issue number1
DOIs
StatePublished - Jan 2012
Externally publishedYes

Keywords

  • Amphiphiles
  • Atomic force microscopy
  • Biosensor
  • Diagnostics
  • LAM atomistic model
  • Lipoarabinomannan
  • Mass spectrometry
  • Supported lipid bilayers

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Microbiology (medical)
  • Infectious Diseases

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