Subcellular localization of the magnetosome protein MamC in the marine magnetotactic bacterium Magnetococcus marinus strain MC-1 using immunoelectron microscopy

Valverde-Tercedor, Carmen; Abadía-Molina, Francisco; Martínez‐Bueno, Manuel; Pineda‐Molina, Estela; Chen, Lijun; Oestreicher, Zachery; Lower, Brian H.; Lower, Steven K.; Bazylinski, Dennis A.; Jiménez-López, Concepción

doi:10.1007/s00203-014-0984-0

Cited by 18 publications

(16 citation statements)

References 37 publications

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“…1a,b and S1a,b,c) show that the purification process was effective, yielding strong bands at 13.8 and 17.4 kDa, corresponding to the expected sizes of the recombinant MamCnts-His and MamC-His proteins. These results are consistent with previous purification studies performed by Valverde-Tercedor et al (2014). In the experiment run with cells containing the vector pTrcHis-TOPO, other weak bands showed up in the gel that were not observed when cells were transformed with pTrcHis-TOPO_mamC (Fig.…”

Section: Resultssupporting

confidence: 95%

Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1

Valverde-Tercedor

Montalbán-López

Pérez-González

et al. 2015

Appl Microbiol Biotechnol

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137

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Magnetotactic bacteria are a diverse group of prokaryotes that share the unique ability of biomineralizing magnetosomes, which are intracellular, membrane-bounded crystals of either magnetite (Fe3O4) or greigite (Fe3S4). Magnetosome biomineralization is mediated by a number of specific proteins, many of which are localized in the magnetosome membrane, and thus is under strict genetic control. Several studies have partially elucidated the effects of a number of these magnetosome-associated proteins in the control of the size of magnetosome magnetite crystals. However, the effect of MamC, one of the most abundant proteins in the magnetosome membrane, remains unclear. In this present study, magnetite nanoparticles were synthesized inorganically in free-drift experiments at 25 °C in the presence of different concentrations of the iron-binding recombinant proteins MamC and MamCnts (MamC without its first transmembrane segment) from the marine, magnetotactic bacterium Magnetococcus marinus strain MC-1 and three commercial proteins [α-lactalbumin (α-Lac), myoglobin (Myo), and lysozyme (Lyz)]. While no effect was observed on the size of magnetite crystals formed in the presence of the commercial proteins, biomimetic synthesis in the presence of MamC and MamCnts at concentrations of 10-60 μg/mL resulted in the production of larger and more well-developed magnetite crystals (~30-40 nm) compared to those of the control (~20-30 nm; magnetite crystals grown protein-free). Our results demonstrate that MamC plays an important role in the control of the size of magnetite crystals and could be utilized in biomimetic synthesis of magnetite nanocrystals.

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Section: Resultssupporting

confidence: 95%

Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1

Valverde-Tercedor

Montalbán-López

Pérez-González

et al. 2015

Appl Microbiol Biotechnol

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137

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“…Cellular localization analyses of magnetosome proteins were investigated using transmission electron microscopy (TEM) (26,27), atomic force microscopy (28), and fluorescence microscopy (29). Fluorescence microscopy is conventionally used with fluorescent-tagged protein-expressing transformants to analyze target protein localization behaviors in living magnetotactic bacteria.…”

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confidence: 99%

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals

et al. 2016

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The magnetosome is an organelle specialized for inorganic magnetite crystal synthesis in magnetotactic bacteria. The complex mechanism of magnetosome formation is regulated by magnetosome proteins in a stepwise manner. Protein localization is a key step for magnetosome development; however, a global study of magnetosome protein localization remains to be conducted. Here, we comparatively analyzed the subcellular localization of a series of green fluorescent protein (GFP)-tagged magnetosome proteins. The protein localizations were categorized into 5 groups (short-length linear, middle-length linear, long-length linear, cell membrane, and intracellular dispersing), which were related to the protein functions. Mms6, which regulates magnetite crystal growth, localized along magnetosome chain structures under magnetite-forming (microaerobic) conditions but was dispersed in the cell under nonforming (aerobic) conditions. Correlative fluorescence and electron microscopy analyses revealed that Mms6 preferentially localized to magnetosomes enclosing magnetite crystals. We suggest that a highly organized spatial regulation mechanism controls magnetosome protein localization during magnetosome formation in magnetotactic bacteria. IMPORTANCEMagnetotactic bacteria synthesize magnetite (Fe 3 O 4 ) nanocrystals in a prokaryotic organelle called the magnetosome. This organelle is formed using various magnetosome proteins in multiple steps, including vesicle formation, magnetosome alignment, and magnetite crystal formation, to provide compartmentalized nanospaces for the regulation of iron concentrations and redox conditions, enabling the synthesis of a morphologically controlled magnetite crystal. Thus, to rationalize the complex organelle development, the localization of magnetosome proteins is considered to be highly regulated; however, the mechanisms remain largely unknown. Here, we performed comparative localization analysis of magnetosome proteins that revealed the presence of a spatial regulation mechanism within the linear structure of magnetosomes. This discovery provides evidence of a highly regulated protein localization mechanism for this bacterial organelle development. P rotein localization at appropriate positions within a cell is an essential mechanism for the effective performance of the diverse biological reactions that occur within the restricted intracellular area in both eukaryotes and prokaryotes. In various prokaryotes, intracellular compartments can be created to provide the domains required for highly specialized reactions. Whereas some of these compartments are completely proteinaceous (e.g., carboxysomes, metabolosomes, and ferritin) (1-3), others contain molecular components similar to those in cell membranes, including lipids and proteins (e.g., nucleoids, polyhydroxybutyrate, and spores) (4, 5). Such compartmentalized organelles are recognized to be formed within bacteria through multiple processes involving the spatial regulation of protein localization, but the details of this regulatory m...

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“…All three have transmembrane domains and loops with charged residues facing the magnetosome lumen that are believed to interact with iron cations Barber-Zuker et al, 2016). In the same way, they display nearly identical localization patterns (Lang and Schüler, 2008;Valverde-Tercedor et al, 2014). Mms6 and MmsF are encoded in the mms6 operon (Lohβe et al, 2014) and both are believed to play a role controlling shape, and in the case of MmsF, controlling crystal maturation as well Murat et al, 2012).…”

Section: Física De La Tierramentioning

confidence: 96%

Magnetita biomimética mediada por proteínas del magnetosoma vs. magnetita del meteorito ALH84001: ¿Son ambas comparables?

Barry-Sosa

Jiménez-López

2016

Fís. Tierra

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The suggestion in 1996 that the Martian meteorite ALH84001 could contain proof of possible biologic activity in the past have generated a huge controversy that last until today. One of the most discussed evidence is the presence of magnetite crystals that resemble those produced by a particular group of bacteria, the so called magnetotactic bacteria (MTB). These microorganisms are the only known example of biologically controlled biomineralization among the prokaryotes and exert an exquisite control over the biomineralization process of intracellular magnetite that result in crystals with very unique features that, so far, cannot be replicated by inorganic means. These unique features have been used to recognize the biological origin of natural terrestrial magnetites, but the problem arises when those same biogenecity criteria are applied to extraterrestrial magnetites. Most of the problems are caused by the fact that it is not clear whether or not some of those characteristics can be reproduced inorganically. Magnetosome protein mediated magnetite synthesis seems to be the best approach to obtain magnetosome-like magnetites, and such strategy may help clarify what is the specific biosignature of magnetotactic bacteria. Key words: ALH84001; Magnetite; MPMS (Magnetosome Protein Mediated Synthesis); Magnetotactic bacteria.Magnetita biomimética mediada por proteínas del magnetosoma vs. magnetita del meteorito ALH84001: ¿Son ambas comparables?Resumen La sugerencia en 1996 de que el meteorito marciano ALH84001 pudiese contener pruebas de posible actividad biológica en el pasado ha generado una gran controversia que aún persiste hoy. Una de las evidencias más discutidas es la presencia de cristales de magnetita que se asemejan a aquellos producidos por un grupo particular de bacterias, las bacterias magnetotácticas (MTB). Estos microorganismos son el único ejemplo de mineralización controlado biológicamente conocido entre procariotas y ejerce un control delicado sobre el proceso de biomineralización de la magnetita intracelular que resulta en la formación de cristales con características únicas que, hasta ahora, no han podido ser replicadas por medios inorgánicos. Estas características únicas se han usado para reconocer el origen biológico de magnetitas terrestres naturales, pero el problema aparece cuando los mismos criterios de biogenicidad se aplican a magnetitas extraterrestres. La mayoría de los problemas se deben a que no está claro si alguna de esas características puede ser reproducida inorgánicamente. La síntesis mediada por proteínas del magnetosoma parece ser la mejor aproximación para obtener magnetitas similares a las de los magneto- A. Barry-Sosa, C. Jiménez-LópezBiomimetic magnetite vs.ALH84001 meteorite Física de la Tierra

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Subcellular localization of the magnetosome protein MamC in the marine magnetotactic bacterium Magnetococcus marinus strain MC-1 using immunoelectron microscopy

Cited by 18 publications

References 37 publications

Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1

Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals

Magnetita biomimética mediada por proteínas del magnetosoma vs. magnetita del meteorito ALH84001: ¿Son ambas comparables?

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