Combined Spectroscopic and Topographic Characterization of Nanoscale Domains and Their Distributions of a Redox Protein on Bacterial Cell Surfaces

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• 作者：Vasudevanpillai Biju ; Duohai Pan ; Yuri A. Gorby ; Jim Fredrickson ; Jeff McLean ; Daad Saffarini ; H. Peter Lu
• 刊名：Langmuir
• 出版年：2007
• 出版时间：January 30, 2007
• 年：2007
• 卷：23
• 期：3
• 页码：1333 - 1338
• 全文大小：340K
• 年卷期：v.23,no.3(January 30, 2007)
• ISSN：1520-5827

文摘

Redox protein nanoscale domains on the cell surface of a bacterium, Shewanella oneidensis MR1, grown in theabsence and presence of electron acceptors, is topographically characterized using combined atomic force microscopy(AFM) and confocal surface enhanced Raman scattering (SERS) spectroscopy. The protruding nanoscale domainson the outer membrane of S. oneidensis were observed, as was their disappearance upon exposure to electron acceptorssuch as oxygen, nitrate, fumarate, and iron nitrilotriacetate (FeNTA). Using SERS spectroscopy, a redox heme proteinwas identified as a major component of the cell surface domains. This conclusion was further confirmed by thedisappearance of Raman vibrational frequencies, characteristic of heme proteins, upon exposure of the cells to electronacceptors. Our experimental results from our AFM imaging and SERS spectroscopy, consistent with the literature,suggest the protruding nanoscale surface domains as heme-containing secretions. Our results on the distributions ofredox proteins on microbial cell surfaces will be helpful for a mechanistic understanding of the behaviors of surfaceproteins and their interactions with redox environments.