Fig. 1

Protein polymerization by OaAEP1. a Principle of OaAEP1-alone for protein polymerization is based on a GL-POI-NGL protein unit in which an N-terminal NGL (colored in red) reacts with a C-terminal GL (colored in blue) and leads an NGL linkage. b–d The PAGE gel results of ubiquitin polymerization indicate the formation of a protein polymer mixture with a varied length under different conditions. The reaction is fast (completed in 20 min) with the formation of protein polymer at least up to a pentamer (b). The polymerization is robust under acidic pH from 4 to 7 (c), as well as in the presence of most biologically-relevant metal ions (d), except Hg