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A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site.
Hosseinzadeh, Parisa; Tian, Shiliang; Marshall, Nicholas M; Hemp, James; Mullen, Timothy; Nilges, Mark J; Gao, Yi-Gui; Robinson, Howard; Stahl, David A; Gennis, Robert B; Lu, Yi.
Afiliação
  • Robinson H; Biology Department, Brookhaven National Laboratory , Upton, New York 11973-5000, United States.
  • Stahl DA; Department of Civil and Environmental Engineering, University of Washington , Seattle, Washington 98195, United States.
J Am Chem Soc ; 138(20): 6324-7, 2016 05 25.
Article em En | MEDLINE | ID: mdl-27120678
ABSTRACT
Mononuclear cupredoxin proteins usually contain a coordinately saturated type 1 copper (T1Cu) center and function exclusively as electron carriers. Here we report a cupredoxin isolated from the nitrifying archaeon Nitrosopumilus maritimus SCM1, called Nmar1307, that contains a T1Cu center with an open binding site containing water. It displays a deep purple color due to strong absorptions around 413 nm (1880 M(-1) cm(-1)) and 558 nm (2290 M(-1) cm(-1)) in the UV-vis electronic spectrum. EPR studies suggest the protein contains two Cu(II) species of nearly equal population, one nearly axial, with hyperfine constant A∥ = 98 × 10(-4) cm(-1), and another more rhombic, with a smaller A∥ value of 69 × 10(-4) cm(-1). The X-ray crystal structure at 1.6 Å resolution confirms that it contains a Cu atom coordinated by two His and one Cys in a trigonal plane, with an axial H2O at 2.25 Å. Both UV-vis absorption and EPR spectroscopic studies suggest that the Nmar1307 can oxidize NO to nitrite, an activity that is attributable to the high reduction potential (354 mV vs SHE) of the copper site. These results suggest that mononuclear cupredoxins can have a wide range of structural features, including an open binding site containing water, making this class of proteins even more versatile.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Azurina / Archaea / Cobre Idioma: En Ano de publicação: 2016 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Azurina / Archaea / Cobre Idioma: En Ano de publicação: 2016 Tipo de documento: Article