If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Physical Chemistry

Protein Uses A High-Low Approach To Traffic Gold

Chemical Bonding: GolB uses a combination of high gold affinity and weak gold bonding to prevent toxic accumulation of the metal in cells

by Stu Borman
December 21, 2015 | A version of this story appeared in Volume 93, Issue 49

Credit: J. Am. Chem. Soc.
Crystal structure of gold-bound GolB protein.
Crystal structure of Au-bound GolB protein shows its two Au–S bonds.
Credit: J. Am. Chem. Soc.
Crystal structure of gold-bound GolB protein.

A study on gold-sulfur coordination in GolB, a bacterial protein, shows how it and possibly similar proteins protect cells from toxic amounts of metals. GolB scavenges gold to prevent the metal’s cytoplasmic concentration from getting high enough to poison cells. The protein is known to have high affinity for gold, which it takes up by forming covalent Au–S coordination bonds. But researchers have not known how GolB is able to readily transfer gold to another protein that moves gold outside the cell. Using single-molecule force spectroscopy, Yi Cao and Jing Zhao of Nanjing University and coworkers found that the strength of each of GolB’s Au–S bonds is 165 pN, much weaker than the 500- to 1,000-pN strength of other Au–S bonds, such as those of self-assembled monolayers used in some molecular electronics and sensors (J. Am. Chem. Soc. 2015, DOI: 10.1021/jacs.5b09895). The team’s crystal structures also show GolB Au–S bonds (2.55 Å) to be longer than Au–S bonds on gold surfaces (2.40 Å). So it’s the high affinity for gold and weak Au–S bonds that allow GolB to capture and transfer gold easily, the researchers conclude. They speculate that this high-low effect may also be at work in other metal-trafficking proteins.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.