Title
Protein Conservation Method Affects MamC-Mediated Biomineralization of Magnetic Nanoparticles
Author
Ylenia Jabalera, Salvador Casares Atienza, Antonia Fernández-Vivas, Ana Peigneux, Ana I. Azuaga Fortes, Concepcion Jimenez-Lopez
Year
2019
Journal
Crystal Growth & Design
Abstract
Magnetite nanoparticles in the magnetosomes formed by magnetotactic bacteria present unique magnetic properties that make them the ideal nanoparticle with potential use in several biotechnological applications. These magnetoliposomes are organelles formed by crystals of magnetite (Fe3O4) or greigite (Fe3S4) surrounded by a lipid bilayer. However, scaling up the production of these nanoparticles cannot be achieved currently because of the slow growth and the strict physiological characteristics of the magnetotactic bacteria. An alternative to solve this problem is the biomimetic approach, which involves the in vitro production of magnetite nanoparticles mediated by magnetosome membrane proteins, expressed as recombinant. MamC-mediated magnetite nanoparticles (BMNPs) have been recently proposed as some of the best biomimetic (magnetosome-like) nanoparticles for potential use in targeted drug delivery and hyperthermia treatments. However, the production of these crystals still needs to be scaled up. One of the critical steps in this scaling-up process is to find a method to keep the protein used as a template, MamC, fully functional over time, so that large amounts of protein could be produced at once. Since it has been previously demonstrated that the function of MamC in producing nanoparticles with optimal conditions is strictly linked to its structure, much care needs to be paid to ensure that such a structure is not affected by the protein preservation method. In the present study, MamC was produced and preserved under different conditions (lyophilization, cryoconservation, and refrigeration) for different time intervals. The efficiency of each preservation treatment was evaluated by studying the MamC conformation and oligomerization state and by analyzing the biomimetic crystals formed in the presence of this specific protein. Among all the methodologies assayed, only cryopreservation was able to keep the correct MamC structure and oligomerization state and, therefore, its activity.
Full Article
Instrument
J-715
Keywords
Circular dichroism, Secondary structure, Aggregation, Protein folding, Biochemistry