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1 H NMR spectroscopy of the binuclear Cu(II) active site of Streptomyces antibioticus tyrosinase
Author(s) -
Bubacco Luigi,
Salgado Jesús,
Tepper Armand W.J.W.,
Vijgenboom Erik,
Canters Gerard W.
Publication year - 1999
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/s0014-5793(98)01662-7
Subject(s) - tyrosinase , chemistry , nuclear magnetic resonance spectroscopy , spectroscopy , streptomyces , stereochemistry , crystallography , enzyme , biochemistry , biology , bacteria , physics , quantum mechanics , genetics
The 600 MHz 1 H NMR spectrum of tyrosinase (31 kDa) of Streptomyces antibioticus in the oxidized, chloride‐bound form is reported. The downfield part of the spectrum (15–55 ppm) exhibits a large number of paramagnetically shifted signals. The paramagnetism is ascribed to a thermally populated triplet state. The signals derive from six histidines binding to the metals through their Nϵ atoms. There is no evidence for endogenous bridges. The exchange coupling, −2 J , amounts to 298 cm −1 . In the absence of chloride the peaks broaden. This is ascribed to a slowing down of the electronic relaxation. The exchange coupling decreases to −2 J =103 cm −1 .