Particle size effect and the mechanism of hematite reduction by the   outer membrane cytochrome OmcA of Shewanella oneidensis MR-1

doi:10.1016/j.gca.2016.08.022

CORC > 北京大学 > 环境科学与工程学院

	Particle size effect and the mechanism of hematite reduction by the outer membrane cytochrome OmcA of Shewanella oneidensis MR-1
	Liu, Juan ; Pearce, Carolyn I. ; Shi, Liang ; Wang, Zheming ; Shi, Zhi ; Arenholz, Elke ; Rosso, Kevin M.
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
	2016
关键词	Hematite Nanoparticle Size effect Microbial iron reduction Aggregation electron transfer Cytochrome MAGNETIC CIRCULAR-DICHROISM C-TYPE CYTOCHROME DISSIMILATORY IRON REDUCTION ELECTRON-TRANSFER FE3-XTIXO4 NANOPARTICLES MICROBIAL REDUCTION AGGREGATION STATE SURFACE-STRUCTURE IRON(III) OXIDES SITE OCCUPANCY
DOI	10.1016/j.gca.2016.08.022
英文摘要	The cycling of iron at the Earth's near surface is profoundly influenced by dissimilatory metal reducing microorganisms, and many studies have focused on unraveling electron transfer mechanisms between these bacteria and Fe(III)-(oxyhydr) oxides. However, these efforts have been complicated by the fact that these minerals often occur in the micro- to nanosize regime, and in relevant natural environments as well as in the laboratory are subject to aggregation. The nature of the physical interface between the cellular envelope, the outer-membrane cytochromes responsible for facilitating the interfacial electron transfer step, and these complex mineral particulates is thus difficult to probe. Previous studies using whole cells have reported reduction rates that do not correlate with particle size. In the present study we isolate the interaction between the decaheme outer-membrane cytochrome OmcA of Shewanella oneidensis and nanoparticulate hematite, examining the reduction rate as a function of particle size and reaction products through detailed characterization of the electron balance and the structure and valence of iron at particle surfaces. By comparison with abiotic reduction via the smaller molecule ascorbic acid, we show that the reduction rate is systematically controlled by the sterically accessible interfacial contact area between OmcA and hematite in particle aggregates; rates increase once pore throat sizes in aggregates become as large as OmcA. Simultaneous measure of OmcA oxidation against Fe(II) release shows a ratio of 1: 10, consistent with a cascade OmcA oxidation mechanism heme by heme. X-ray absorption spectroscopies reveal incipient magnetite on the reacted surfaces of the hematite nanoparticles after reaction. The collective findings establish the importance of accessibility of physical contact between the terminal reductases and iron oxide surfaces, and through apparent consistency of observations help reconcile behavior reported at the larger more complex scale of whole cell studies. (C) 2016 Elsevier Ltd. All rights reserved.; PNNL Science Focus Area project - U.S. Department of Energy (DOE) Office of Biological and Environmental Research (OBER), Subsurface Biogeochemical Research program; DOE Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Bio-sciences Division; National Natural Science Foundation of China [41472306]; DOE OBER located at PNNL; DOE Office of Science, Office of Basic Energy Sciences [DE-AC02-05CH11231]; SCI(E); ARTICLE; juan.liu@pku.edu.cn; kevin.rosso@pnl.gov; 160-175; 193
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/458443]
专题	环境科学与工程学院
推荐引用方式 GB/T 7714	Liu, Juan,Pearce, Carolyn I.,Shi, Liang,et al. Particle size effect and the mechanism of hematite reduction by the outer membrane cytochrome OmcA of Shewanella oneidensis MR-1[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2016.
APA	Liu, Juan.,Pearce, Carolyn I..,Shi, Liang.,Wang, Zheming.,Shi, Zhi.,...&Rosso, Kevin M..(2016).Particle size effect and the mechanism of hematite reduction by the outer membrane cytochrome OmcA of Shewanella oneidensis MR-1.GEOCHIMICA ET COSMOCHIMICA ACTA.
MLA	Liu, Juan,et al."Particle size effect and the mechanism of hematite reduction by the outer membrane cytochrome OmcA of Shewanella oneidensis MR-1".GEOCHIMICA ET COSMOCHIMICA ACTA (2016).