Neb 10 beta competent e coli cells

Plasmid transformations and amplifications were performed using NEB® 10-beta competent E. coli cells (New England BioLabs, Inc.). Maxiprep DNA purifications were performed using the ZymoPURE II Plasmid Maxiprep Kit (Zymo Research, Corp., Irvine, CA). All maxipreped DNA were quantified using a Thermo Scientific™ Invitrogen™ Nanodrop™ One Spectrophotometer (ThermoFisher Scientific, Inc.). All maxipreped DNA were diluted down to a final concentration of 1000 μg/μL and stored at − 20 °C. The quality and quantity of all maxipreped DNA was estimated by restriction analysis and agarose gel electrophoresis.

Three Rhodobacter capsulatus strains were used in this study: rifampicin sensitive wild-type strain B10 (Wall et al., 1975 (link)), a rifampicin resistant derivative SB1003 (ATCC BAA-309) and an RcGTA overproducer strain DE442 (Ding et al., 2014 ; Fogg et al., 2012 (link)). All R. capsulatus cultures were grown at 30°C either aerated in the dark or in anoxic sealed tubes under constant illumination. Two growth media were used – YPS complex broth (0.3% w/v yeast extract, 0.3% w/v peptone, 2 mM MgCl₂, 2 mM CaCl₂) or RCV defined broth (10 mM potassium phosphate buffer, 0.4% w/v L-malic acid, 0.1% w/v (NH₄)₂SO₄, 0.020% w/v MgSO₄^.7H₂O, 0.0075% w/v CaCl₂^.2H₂O, 0.0012% w/v FeSO₄^.7H₂O, 0.0020% w/v Na₂EDTA, 0.0001% w/v thiamine hydrochloride. Plus 1 mL of trace element solution - 0.07% w/v H₃BO₃, 0.040% w/v MnSO₄^.H₂O, 0.019% w/v Na₂MoO₄^.2H₂O, 0.006% w/v ZnSO₄^.7H₂O, 0.001% w/v Cu(NO₃)^.3H₂O. The pH was adjusted to 6.8 with NaOH). For agar plates, 1.5% w/v agar was added to the above broth recipes. The E. coli S17-1 strain (DSM 9079), which contains chromosomally integrated tra genes, was used as a donor for all conjugations. NEB 10-beta Competent E. coli cells (New England Biolabs) were used for standard cloning and plasmid maintenance; T7 Express Competent E. coli cells (New England Biolabs) were used for overexpression of proteins for purification.