Finally out in Nature Chem Bio:
SNAP-tag2 for faster and brighter protein labeling
www.nature.com/articles/s41...
Thank you Steffi and Veselin.

SNAP-tag2 for faster and brighter protein labeling - Nature Chemical Biology
SNAP-tag is a widespread tool for labeling protein for bioimaging. Now, Kühn et al. report SNAP-tag2 with increased labeling kinetics and brightness, which translates into a better performance in live...