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The crystal structures of reduced pseudoazurin from Alcaligenes faecalis S‐6 at two pH values
Author(s) -
Vakoufari Eleni,
Wilson Keith S.,
Petratos Kyriacos
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00544-3
Subject(s) - alcaligenes faecalis , chemistry , biology , genetics , bacteria
The structures of the reduced (Cu 1+ ) blue‐copper protein pseudoazurin from Alcaligenes faecalis strain S‐6 are refined at pH 7.8 and 4.4 using X‐ray diffraction data to 1.8 Å resolution. The final R ‐factors for the high and low pH structures are 0.178 and 0.177, respectively. Comparing the reduced pseudoazurin at pH 7.8 with the oxidised (Cu 2+ ) molecule, small changes are observed in the vicinity of the copper site and on the protein surface. At pH 4.4 the copper substituent imidazole of His 81 rotates away from the metal with a concurrent movement of the latter towards the plane of the remaining three ligands (Sγ‐Cys 78 , Nδl‐His 40 and Sδ‐Met 86 ) thus the geometry of the copper site becomes planar trigonal.