Fig. S3.

Photobiochemical properties of the full-length T. elongatus SesB holoprotein expressed in and purified from the cyanobacterial expression system. (A) SDS/PAGE. CBB, Coomassie brilliant blue stain; Fluo, fluorescence before (–) and after (+) Zn²⁺ addition. (B) Photoconversion. The SesB Pb absorption spectrum induced by irradiation with teal light is shown in blue. The SesB Pt absorption spectrum induced by irradiation with blue light is shown in teal. (C) The white light-induced difference spectra of the chromophore (C15-E – C15-Z) for the urea/acid-denatured SesB. (D) SesB is a PDE (c-di-GMP→pGpG) activated by teal light and GTP. NAD served as the internal control. Reaction mixtures, including 100 µM c-di-GMP, were incubated for 10 min under blue light (Left) or teal light (Right). Addition of 100 µM GTP (Lower) under both light conditions enhanced PDE activity, compared with reactions performed without GTP (Upper).