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Low resolution structural determination of lipoprotein6.6: a membrane component of Borrelia burgdorferi (753.2)
Author(s) -
Freeman David,
Kumru Ozan,
Middaugh C.,
Joshi Sangeeta,
Zückert Wolfram
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.753.2
Subject(s) - circular dichroism , borrelia burgdorferi , chemistry , bacterial outer membrane , biophysics , protein tertiary structure , dynamic light scattering , recombinant dna , periplasmic space , fluorescence spectroscopy , random coil , biochemistry , fluorescence , biology , materials science , nanotechnology , physics , escherichia coli , quantum mechanics , gene , nanoparticle , antibody , immunology
Recent studies conducted on Borrelia burgdorferi, the causative agent of Lyme disease, have focused on lipoproteins. Lipoprotein 6.6 (Lp6.6) has been shown to play a vital role in the transmission from the Ixodes tick vector to the mammalian host. Lp6.6 is highly abundant in the periplasmic leaflet of the outer membrane and is part of a number of protein complexes. The objectives of this study were to purify a recombinant form of Lp6.6 and gain some insight as to the structure of Lp6.6 by using various low‐resolution spectroscopic techniques. A recombinant non‐lipidated form of Lp6.6 was produced in E. coli and purified using nickel affinity chromatography. Lp6.6 was then studied by far‐UV circular dichroism, dynamic light scattering, and extrinsic fluorescence spectroscopy. Circular dichroism measurements indicate Lp6.6 contains random coil (negative peak at ~200nm) and α‐helix (positive peak at ~190nm). Dynamic light scattering measurements suggests some aggregates are present after proteolytic removal of the 6xHis tag. Extrinsic fluorescence spectroscopy, using 8‐Anilino‐1‐naphthalenesulfonic acid as a probe for exposed hydrophobic moieties, showed an increase in fluorescence at ~45°C, suggesting a perturbation in tertiary structure. Taken together, Lp6.6 has structural components that may be a vital part of outer membrane protein complexes.