5FC9

Novel Purple Cupredoxin from Nitrosopumilus maritimus

Summary for 5FC9

• Entry DOI: 10.2210/pdb5fc9/pdb
• Descriptor: Blue (Type 1) copper domain protein, COPPER (II) ION (3 entities in total)
• Functional Keywords: cupredoxin, no oxidation, nitrogen cycle, open type 1 copper site, metal binding protein
• Biological source: Nitrosopumilus maritimus (strain SCM1)
• Total number of polymer chains: 4
• Total formula weight: 42808.57

Authors

Hosseinzadeh, P.,Lu, Y.,Robinson, H.,Gao, Y.-G. (deposition date: 2015-12-15, release date: 2016-05-11, Last modification date: 2023-09-27)

Primary citation

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.
A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site.
J.Am.Chem.Soc., 138:6324-6327, 2016

PubMed 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.

PubMed: 27120678
DOI: 10.1021/jacs.5b13128

Experimental method

X-RAY DIFFRACTION (1.6 Å)