TY - JOUR
T1 - Metal-binding properties of an engineered purple Cu(A) center in azurin
AU - Hay, Michael T.
AU - Lu, Yi
N1 - Funding Information:
Acknowledgements We thank Dalton McLean for assistance in reproducing some of the experimental results, Richard Milberg for collecting the ESI-MS spectra, and Steven M. Berry for a critical reading of the manuscript. This material is based upon work supported by the National Science Foundation under award no. CHE 95-02421 to Y.L. (CAREER Award and Special Creativity Extension). Y.L. is a Sloan Research Fellow of the Alfred Sloan Foundation, a Cottrell Scholar of the Research Corporation, a Camille Dreyfus Teacher-Scholar of the Camille and Henry Dreyfus Foundation, and a Beckman Young Investigator of the Arnold and Mabel Beckman Foundation.
PY - 2000
Y1 - 2000
N2 - A Cu(A) center engineered into Pseudomonas aeruginosa azurin was studied by metal substitution. Metal-binding properties were determined by electronic absorption (UV-vis) and electrospray ionization mass spectrometry (ESI-MS). The metal-binding site readily binds thiophilic metal ions, such as Hg(II), Ag(I), Cu(I), Cd(II), and Au(I). Harder metal ions, like Co(II), bind to apo-Cu(A)-azurin only under basic conditions (pH 9.1-9.2). The results obtained from these studies indicate that two factors influence metal binding in Cu(A) azurin: (1) the site favors metal combinations which produce an overall +3 charge, and (2) the site binds soft, thiophilic metal ions. The results demonstrate the remarkable ability of the Cu(A) center to maintain valence delocalization of its native metal ions and to ensure redox accessibility of only one of the two redox couples (i.e., [Cu(1.5)···Cu(1.5)]⇆ [Cu (I)···Cu(I)]) under physiological conditions. These findings may lead to the preparation of new metal ion derivatives and can serve as a basis for understanding this efficient electron transfer center.
AB - A Cu(A) center engineered into Pseudomonas aeruginosa azurin was studied by metal substitution. Metal-binding properties were determined by electronic absorption (UV-vis) and electrospray ionization mass spectrometry (ESI-MS). The metal-binding site readily binds thiophilic metal ions, such as Hg(II), Ag(I), Cu(I), Cd(II), and Au(I). Harder metal ions, like Co(II), bind to apo-Cu(A)-azurin only under basic conditions (pH 9.1-9.2). The results obtained from these studies indicate that two factors influence metal binding in Cu(A) azurin: (1) the site favors metal combinations which produce an overall +3 charge, and (2) the site binds soft, thiophilic metal ions. The results demonstrate the remarkable ability of the Cu(A) center to maintain valence delocalization of its native metal ions and to ensure redox accessibility of only one of the two redox couples (i.e., [Cu(1.5)···Cu(1.5)]⇆ [Cu (I)···Cu(I)]) under physiological conditions. These findings may lead to the preparation of new metal ion derivatives and can serve as a basis for understanding this efficient electron transfer center.
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U2 - 10.1007/s007750000158
DO - 10.1007/s007750000158
M3 - Article
C2 - 11128997
AN - SCOPUS:0033739720
SN - 0949-8257
VL - 5
SP - 699
EP - 712
JO - Journal of Biological Inorganic Chemistry
JF - Journal of Biological Inorganic Chemistry
IS - 6
ER -