Structural Insights and the Surprisingly Low Mechanical Stability of the Au–S Bond in the Gold-Specific Protein GolB
Wei Wei†‡, Yang Sun§, Mingli Zhu†‡, Xiangzhi Liu†‡, Peiqing Sun†‡, Feng Wang∥, Qiu Gui‡, Wuyi Meng∥, Yi Cao*§, and Jing Zhao*†‡
†State Key Laboratory of Coordination Chemistry, Institute of Chemistry
and BioMedical Sciences, School of Chemistry and Chemical Engineering,
Collaborative Innovation Center of Chemistry for Life Sciences, ‡State Key Laboratory
of Pharmaceutical Biotechnology, School of Life Sciences, and §Collaborative Innovation
Center of Advanced Microstructures, National Laboratory of Solid State
Microstructure, Department of Physics, Nanjing
University, Nanjing 210093, China
∥ Elias
James Corey Institute of Biomedical Research, Wuxi Biortus Biosciences Co., Ltd, Jiangyin, 214437, China
J. Am. Chem. Soc., Article ASAP
DOI: 10.1021/jacs.5b09895
Abstract
The
coordination bond between gold and sulfur (Au–S) has been widely
studied and utilized in many fields. However, detailed investigations on
the basic nature of this bond are still lacking. A gold-specific
binding protein, GolB, was recently identified, providing a unique
opportunity for the study of the Au–S bond at the molecular level. We
probed the mechanical strength of the gold–sulfur bond in GolB using
single-molecule force spectroscopy. We measured the rupture force of the
Au–S bond to be 165 pN, much lower than Au–S bonds measured on
different gold surfaces (∼1000 pN). We further solved the structures of
apo-GolB and Au(I)–GolB complex using X-ray crystallography. These
structures showed that the average Au–S bond length in GolB is much
longer than the reported average value of Au–S bonds. Our results
highlight the dramatic influence of the unique biological environment on
the stability and strength of metal coordination bonds in proteins.
http://dx.doi.org/10.1021/jacs.5b09895
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