Rapid magnetosome formation shown by real-time x-ray magnetic circular dichroism

Staniland, Sarah; Ward, Bruce; Harrison, Andrew; van der Laan, Gerrit; Telling, Neil

Abstract

Magnetosomes are magnetite nanoparticles formed by biomineralization within magnetotactic bacteria. Although there have been numerous genetic and proteomic studies of the magnetosome-formation process, there have been only limited and inconclusive studies of mineral-phase evolution during the formation process, and no real-time studies of such processes have yet been performed. Thus, suggested formation mechanisms still need substantiating with data. Here we report the examination of the magnetosome material throughout the formation process in a real-time in vivo study of Magnetospirillum gryphiswaldense, strain MSR-1. Transmission EM and x-ray absorption spectroscopy studies reveal that full-sized magnetosomes are seen 15 min after formation is initiated. These immature magnetosomes contain a surface layer of the nonmagnetic iron oxide-phase hematite. Mature magnetite is found after another 15 min, concurrent with a dramatic increase in magnetization. This rapid formation result is contrary to previously reported studies and discounts the previously proposed slow, multistep formation mechanisms. Thus, we conclude that the biomineralization of magnetite occurs rapidly in magnetotactic bacteria on a similar time scale to high-temperature chemical precipitation reactions, and we suggest that this finding is caused by a biological catalysis of the process.

Citation

Staniland, S., Ward, B., Harrison, A., van der Laan, G., & Telling, N. (2007). Rapid magnetosome formation shown by real-time x-ray magnetic circular dichroism. Proceedings of the National Academy of Sciences of the United States of America, 104(49), 19524-19528. https://doi.org/10.1073/pnas.0704879104

• Journal Article Type: Article
• Acceptance Date: Oct 12, 2007
• Online Publication Date: Dec 4, 2007
• Publication Date: Dec 4, 2007
• Deposit Date: May 17, 2024
• Journal: Proceedings of the National Academy of Sciences
• Print ISSN: 0027-8424
• Electronic ISSN: 1091-6490
• Publisher: National Academy of Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 104
• Issue: 49
• Pages: 19524-19528
• DOI: https://doi.org/10.1073/pnas.0704879104
• Public URL: https://keele-repository.worktribe.com/output/829073
• Additional Information: Received: 2007-05-24; Published: 2007-12-04