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Title: Kinetics of α-MnOOH Nanoparticle Formation through Enzymatically Catalyzed Biomineralization inside Apoferritin

Abstract

While biomineralization in apoferritin has effectively synthesized highly monodispersed nanoparticles of various metal oxides and hydroxides, the detailed kinetics and mechanisms of Mn(III) (hydr)oxide formation inside apoferritin cavities have not been reported. To address this knowledge gap, we first identified the phase of solid Mn(III) formed inside apoferritin cavities as α-MnOOH. To analyze the oxidation and nucleation mechanism of α-MnOOH inside apoferritin by quantifying oxidized Mn, we used a colorimetric method with leucoberbelin blue (LBB) solution. In this method, LBB disassembled apoferritin by inducing an acidic pH environment, and reduced α-MnOOH nanoparticles. The LBB-enabled kinetic analyses of α-MnOOH nanoparticle formation suggested that the orders of reaction with respect to Mn2+ and OH– are 2 and 4, respectively, and α-MnOOH formation follows two-step pathways: First, soluble Mn2+ undergoes apoferritin-catalyzed oxidation at the ferroxidase dinuclear center, forming a Mn(III)-protein complex, P-[Mn2O2(OH)2]. Second, the oxidized Mn(III) dissociates from the protein binding sites and is subsequently nucleated to form α-MnOOH nanoparticles in the apoferritin cavities. This study reveals key kinetics and mechanistic information on the Mn-apoferritin systems, and the results facilitate applications of apoferritin as a means of nanomaterial synthesis.

Authors:
 [1];  [1];  [1]; ORCiD logo [1]
  1. Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1408131
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystal Growth and Design; Journal Volume: 17; Journal Issue: 11
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Hui, Yue, Jung, Haesung, Kim, Doyoon, and Jun, Young-Shin. Kinetics of α-MnOOH Nanoparticle Formation through Enzymatically Catalyzed Biomineralization inside Apoferritin. United States: N. p., 2017. Web. doi:10.1021/acs.cgd.7b00568.
Hui, Yue, Jung, Haesung, Kim, Doyoon, & Jun, Young-Shin. Kinetics of α-MnOOH Nanoparticle Formation through Enzymatically Catalyzed Biomineralization inside Apoferritin. United States. doi:10.1021/acs.cgd.7b00568.
Hui, Yue, Jung, Haesung, Kim, Doyoon, and Jun, Young-Shin. Fri . "Kinetics of α-MnOOH Nanoparticle Formation through Enzymatically Catalyzed Biomineralization inside Apoferritin". United States. doi:10.1021/acs.cgd.7b00568.
@article{osti_1408131,
title = {Kinetics of α-MnOOH Nanoparticle Formation through Enzymatically Catalyzed Biomineralization inside Apoferritin},
author = {Hui, Yue and Jung, Haesung and Kim, Doyoon and Jun, Young-Shin},
abstractNote = {While biomineralization in apoferritin has effectively synthesized highly monodispersed nanoparticles of various metal oxides and hydroxides, the detailed kinetics and mechanisms of Mn(III) (hydr)oxide formation inside apoferritin cavities have not been reported. To address this knowledge gap, we first identified the phase of solid Mn(III) formed inside apoferritin cavities as α-MnOOH. To analyze the oxidation and nucleation mechanism of α-MnOOH inside apoferritin by quantifying oxidized Mn, we used a colorimetric method with leucoberbelin blue (LBB) solution. In this method, LBB disassembled apoferritin by inducing an acidic pH environment, and reduced α-MnOOH nanoparticles. The LBB-enabled kinetic analyses of α-MnOOH nanoparticle formation suggested that the orders of reaction with respect to Mn2+ and OH– are 2 and 4, respectively, and α-MnOOH formation follows two-step pathways: First, soluble Mn2+ undergoes apoferritin-catalyzed oxidation at the ferroxidase dinuclear center, forming a Mn(III)-protein complex, P-[Mn2O2(OH)2]. Second, the oxidized Mn(III) dissociates from the protein binding sites and is subsequently nucleated to form α-MnOOH nanoparticles in the apoferritin cavities. This study reveals key kinetics and mechanistic information on the Mn-apoferritin systems, and the results facilitate applications of apoferritin as a means of nanomaterial synthesis.},
doi = {10.1021/acs.cgd.7b00568},
journal = {Crystal Growth and Design},
number = 11,
volume = 17,
place = {United States},
year = {Fri Sep 29 00:00:00 EDT 2017},
month = {Fri Sep 29 00:00:00 EDT 2017}
}