Fukuda Y, Mizohata E, Inoue T. New molecular packing in a crystal of pseudoazurin from Alcaligenes faecalis: a double-helical arrangement of blue copper.
Acta Crystallogr F Struct Biol Commun 2017;
73:159-166. [PMID:
28291752 PMCID:
PMC5349310 DOI:
10.1107/s2053230x17002631]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 02/15/2017] [Indexed: 11/10/2022] Open
Abstract
Pseudoazurin from the denitrifying bacterium Alcaligenes faecalis (AfPAz) is a blue copper protein and functions as an electron donor to copper-containing nitrite reductase (CuNIR). Conventionally, AfPAz has been crystallized using highly concentrated ammonium sulfate as a precipitant. Here, a needle-like crystal of AfPAz grown in a solution containing a macromolecular precipitant, polyethylene glycol 8000 (PEG 8000), is reported. The crystal belonged to space group P61, with unit-cell parameters a = b = 68.7, c = 94.2 Å. The structure has been determined and refined at 2.6 Å resolution. The asymmetric unit contained two AfPAz molecules contacting each other on negatively charged surfaces. The molecular packing of the crystal showed a right-handed double-helical arrangement of AfPAz molecules and hence of blue copper sites. This structure provides insight into the excluded-volume effect of PEG and the manner of assembly of AfPAz.
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