A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site

Parisa Hosseinzadeh, Shiliang Tian, Nicholas M. Marshall, James Hemp, Timothy Mullen, Mark J. Nilges, Yi Gui Gao, Howard Robinson, David A. Stahl, Robert B. Gennis, Yi Lu

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Pages (from-to)6324-6327
Number of pages4
JournalJournal of the American Chemical Society
Volume138
Issue number20
DOIs
StatePublished - May 25 2016

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site'. Together they form a unique fingerprint.

  • Cite this

    Hosseinzadeh, P., Tian, S., Marshall, N. M., Hemp, J., Mullen, T., Nilges, M. J., Gao, Y. G., Robinson, H., Stahl, D. A., Gennis, R. B., & Lu, Y. (2016). A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site. Journal of the American Chemical Society, 138(20), 6324-6327. https://doi.org/10.1021/jacs.5b13128