The interaction of equine lysozyme:oleic acid complexes with lipid membranes suggests a cargo off-loading mechanism.
Abstract: The normal function of equine lysozyme (EL) is the hydrolysis of peptidoglycan residues of bacterial cell walls. EL is closely related to alpha-lactalbumins with respect to sequence and structure and further possesses the calcium binding site of alpha-lactalbumins. Recently, EL multimeric complexes with oleic acids (ELOAs) were shown to possess tinctorial and morphological properties, similar to amyloidal aggregates, and to be cytotoxic. ELOA's interactions with phospholipid membranes appear to be central to its biological action, similar to human alpha-lactalbumin made lethal to tumor cells. Here, we describe the interaction of ELOA with phospholipid membranes. Confocal scanning laser microscopy shows that ELOA, but not native EL, accumulates on the surface of giant unilamellar vesicles, without inducing significant membrane permeability. Quartz crystal microbalance with dissipation data indicated an essentially non-disruptive binding of ELOA to supported lipid bilayers, leading to formation of highly dissipative and "soft" lipid membrane; at higher concentrations of ELOA, the lipid membrane desorbs from the surface probably as bilayer sheets of vesicles. This membrane rearrangement occurred to a similar extent when free oleic acid (OA) was added, but not when free OA was removed from ELOA by prior incubation with bovine serum albumin, emphasizing the role of OA in this process. NMR data indicated an equilibrium between free and bound OA, which shifts towards free OA as ELOA is progressively diluted, indicating that OA is relatively loosely bound. Activity measurements together with fluorescence spectroscopy and circular dichroism suggested a conversion of ELOA towards a more native-like state on interaction with lipid membranes, although complete refolding was not observed. Altogether, these results suggest that ELOA may act as an OA carrier and facilitate OA transfer to the membrane. ELOA's properties illustrate that protein folding variants may possess specific functional properties distinct from the native protein.
(c) 2010 Elsevier Ltd. All rights reserved.
Publication Date: 2010-03-19 PubMed ID: 20227419DOI: 10.1016/j.jmb.2010.03.012Google Scholar: Lookup
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Summary
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The research investigates how complexes of equine lysozyme and oleic acid (ELOA) interact with lipid membranes and speculates it might have a role in transporting oleic acid to the membrane. The study highlights the distinctive traits of these protein folding variants which are unlike the properties of the original protein.
Study on Equine Lysozyme and Oleic Acid (ELOA)
The experiment conducted by the researchers focused on:
- The relationship, both in structure and sequence, between Equine Lysozyme and alpha-lactalbumins. Equine Lysozyme is a naturally occurring enzyme with bacteriolytic functions.
- The observation that ELOA, which are multimeric complexes of Equine Lysozyme and oleic acids, display characteristics similar to amyloidal aggregates and have cytotoxic abilities.
- An exploration of ELOA’s interactions with phospholipid membranes which appears vital to its biological function.
Interaction of ELOA with Phospholipid Membranes
In examining the interactions, researchers found:
- Through confocal scanning laser microscopy, an accumulation of ELOA, but not the native Equine Lysozyme, on the surface of giant unilamellar vesicles. This process did not lead to a significant increase in membrane permeability.
- When observed through a quartz crystal microbalance with dissipation data, the binding of ELOA to supported lipid bilayers wasn’t disruptive. It led to highly dissipative, “soft” lipid membranes. With increased concentrations of ELOA, the lipid membrane desorbs, potentially in bilayer sheets or vesicles.
- A similar membrane rearrangement occurred when free oleic acid (OA) was introduced, but not when it was removed from ELOA by incubation with bovine serum albumin, emphasizing the importance of OA in this process.
Findings and Conclusions
From the data obtained, conclusions are drawn on the role of ELOA and its potential implications:
- Nuclear magnetic resonance (NMR) data showed a balance between free and bound OA that shifts towards free OA as ELOA is progressively diluted, suggesting that OA is loosely bound.
- Activity measurements, fluorescence spectroscopy, and circular dichroism suggest a conversion of ELOA towards a more native, or original, form on interaction with lipid membranes. However, complete reversion to the original form was not observed.
- Collectively, these findings suggest that ELOA may act as a carrier for OA, facilitating its transfer to the membrane. This highlights the unique functional traits of these protein folding variants that separate them from the properties of the original, or native, protein.
Cite This Article
APA
Nielsen SB, Wilhelm K, Vad B, Schleucher J, Morozova-Roche LA, Otzen D.
(2010).
The interaction of equine lysozyme:oleic acid complexes with lipid membranes suggests a cargo off-loading mechanism.
J Mol Biol, 398(2), 351-361.
https://doi.org/10.1016/j.jmb.2010.03.012 Publication
Researcher Affiliations
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
MeSH Terms
- Amyloid / chemistry
- Animals
- Horses
- Lipid Bilayers / chemistry
- Muramidase / chemistry
- Nuclear Magnetic Resonance, Biomolecular
- Oleic Acid / chemistry
- PC12 Cells
- Phospholipids / chemistry
- Quartz / chemistry
- Rats
- Unilamellar Liposomes / chemistry
Citations
This article has been cited 12 times.- Baksheeva VE, Tiulina VV, Iomdina EN, Petrov SY, Filippova OM, Kushnarevich NY, Suleiman EA, Eyraud R, Devred F, Serebryakova MV, Shebardina NG, Chistyakov DV, Senin II, Mitkevich VA, Tsvetkov PO, Zernii EY. Tear nanoDSF Denaturation Profile Is Predictive of Glaucoma.. Int J Mol Sci 2023 Apr 12;24(8).
- El-Fakharany EM, Redwan EM. Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity.. RSC Adv 2019 Nov 11;9(63):36890-36906.
- Savoldi IR, Ibelli AMG, Cantão ME, Peixoto JO, Pires MP, Mores MAZ, Lagos EB, Lopes JS, Zanella R, Ledur MC. A joint analysis using exome and transcriptome data identifiescandidate polymorphisms and genes involved with umbilical hernia in pigs.. BMC Genomics 2021 Nov 13;22(1):818.
- Foo ACY, Thompson PM, Chen SH, Jadi R, Lupo B, DeRose EF, Arora S, Placentra VC, Premkumar L, Perera L, Pedersen LC, Martin N, Mueller GA. The mosquito protein AEG12 displays both cytolytic and antiviral properties via a common lipid transfer mechanism.. Proc Natl Acad Sci U S A 2021 Mar 16;118(11).
- Jakubec M, Totland C, Rise F, Chamgordani EJ, Paulsen B, Maes L, Matheeussen A, Gundersen LL, Halskau Ø. Bioactive Metabolites of Marine Origin Have Unusual Effects on Model Membrane Systems.. Mar Drugs 2020 Feb 19;18(2).
- Rath EM, Cheng YY, Pinese M, Sarun KH, Hudson AL, Weir C, Wang YD, Håkansson AP, Howell VM, Liu GJ, Reid G, Knott RB, Duff AP, Church WB. BAMLET kills chemotherapy-resistant mesothelioma cells, holding oleic acid in an activated cytotoxic state.. PLoS One 2018;13(8):e0203003.
- Frislev HS, Nielsen J, Nylandsted J, Otzen D. Using Liprotides to Deliver Cholesterol to the Plasma Membrane.. J Membr Biol 2018 Aug;251(4):581-592.
- Frislev HS, Boye TL, Nylandsted J, Otzen D. Liprotides kill cancer cells by disrupting the plasma membrane.. Sci Rep 2017 Nov 9;7(1):15129.
- Nedergaard Pedersen J, Skov Pedersen J, Otzen DE. Liprotides assist in folding of outer membrane proteins.. Protein Sci 2018 Feb;27(2):451-462.
- Clementi EA, Wilhelm KR, Schleucher J, Morozova-Roche LA, Hakansson AP. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.. PLoS One 2013;8(11):e80649.
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- Nakamura T, Aizawa T, Kariya R, Okada S, Demura M, Kawano K, Makabe K, Kuwajima K. Molecular mechanisms of the cytotoxicity of human α-lactalbumin made lethal to tumor cells (HAMLET) and other protein-oleic acid complexes.. J Biol Chem 2013 May 17;288(20):14408-14416.
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