Send to

Choose Destination
ACS Chem Biol. 2019 Apr 19;14(4):619-635. doi: 10.1021/acschembio.8b00919. Epub 2019 Mar 8.

Directed Evolution of Split APEX2 Peroxidase.

Author information

Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States.
Department of Neuroscience , University of California San Diego , La Jolla , California 92093 , United States.
Department of Pharmacology , University of Washington , Seattle , Washington 98195 , United States.
Chan Zuckerberg Biohub , San Francisco , California 94158 , United States.


APEX is an engineered peroxidase that catalyzes the oxidation of a wide range of substrates, facilitating its use in a variety of applications from subcellular staining for electron microscopy to proximity biotinylation for spatial proteomics and transcriptomics. To further advance the capabilities of APEX, we used directed evolution to engineer a split APEX tool (sAPEX). A total of 20 rounds of fluorescence activated cell sorting (FACS)-based selections from yeast-displayed fragment libraries, using 3 different surface display configurations, produced a 200-amino-acid N-terminal fragment (with 9 mutations relative to APEX2) called "AP" and a 50-amino-acid C-terminal fragment called "EX". AP and EX fragments were each inactive on their own but were reconstituted to give peroxidase activity when driven together by a molecular interaction. We demonstrate sAPEX reconstitution in the mammalian cytosol, on engineered RNA motifs within a non-coding RNA scaffold, and at mitochondria-endoplasmic reticulum contact sites.

Supplemental Content

Full text links

Icon for American Chemical Society Icon for PubMed Central
Loading ...
Support Center