Interfacial Properties and Iron Binding to Bacterial Proteins That Promote the Growth of Magnetite Nanocrystals: X-ray Reflectivity and Surface Spectroscopy Studies

TitleInterfacial Properties and Iron Binding to Bacterial Proteins That Promote the Growth of Magnetite Nanocrystals: X-ray Reflectivity and Surface Spectroscopy Studies
Publication TypeJournal Article
Year of Publication2012
AuthorsWang WJ, Bu W, Wang LJ, Palo PE, Mallapragada S, Nilsen-Hamilton M, Vaknin D
Journal TitleLangmuir
Volume28
Pages4274-4282
Date Published03
Type of ArticleArticle
ISBN Number0743-7463
Accession NumberWOS:000301038000029
Keywordsadsorption, air-water-interface, air/water interface, charged, fluorescence, in-situ observation, INTERFACES, kinetics, lysozyme, monolayers, nanoparticles
Abstract

Surface sensitive X-ray scattering and spectroscopic studies have been conducted to determine structural properties of Mms6, the protein in Magnetospirillum magneticum AMB-1 that is implicated as promoter of magnetite nanocrystals growth. Surface pressure versus molecular area isotherms indicate Mms6 forms stable monolayers at the aqueous/vapor interface that are strongly affected by ionic conditions of the subphase. Analysis of X-ray reflectivity from the monolayers shows that the protein conformation at the interface depends on surface pressure and on the presence of ions in the solutions, in particular of iron ions and its complexes. X-ray fluorescence at grazing angles of incidence from the same monolayers allows quantitative determination of surface bound ions to the protein showing that ferric iron binds to Mms6 at higher densities compared to other ions such as Fe2+ or La3+ under similar buffer conditions.

URL<Go to ISI>://WOS:000301038000029
DOI10.1021/la205074n
Alternate JournalLangmuir