2 5 dhba

Growth of S. lugdunensis and S. aureus strains was assessed in C-TMS with serum. Single, isolated colonies were resuspended in 2 ml C-TMS and grown for over 4 h until OD₆₀₀ was above 1. Each culture was normalized to an OD₆₀₀ of 1 and subcultured 1:200 in C-TMS:HS. WT S. lugdunensis as well as S. aureus strains bearing Δsbn and Δsfa mutations are impaired for growth in this media compared to siderophore-producing strains (35 (link), 38 (link)). Human stress hormones were added to the media for a final concentration of 50 μM to assess for catecholamine–iron acquisition for growth enhancement. Dopamine hydrochloride, L-DOPA, DL-NE hydrochloride, (-)-epinephrine, 2,3-dihydroxybenzoic acid (DHBA), and 2,5-DHBA were purchased from Sigma. Chloramphenicol was also included for strains harboring pRMC2 or derivatives. Cultures were grown in a Bioscreen C plate reader (Growth Curves USA) at 37 °C with constant shaking at medium amplitude. OD₆₀₀ was assessed at 15-min intervals; however, for graphical clarity, 4 h intervals are shown.

All reagents and solvents were used without additional purification unless specified otherwise. Poly(ethylene glycol) with molecular mass 5000 Da (PEG5k, M_w/M_n = 1.02) and 11,000 Da (PEG11k, M_w/M_n = 1.04) were purchased from Polysciences, Inc. (Warrington, PA, USA). 2,2-Bis(hydroxymethyl)propionic acid, bis-MPA, (99+%) sodium azide, and NaN₃ (98%, powder) were acquired from Acros. Sodium hydride, NaH, (95%, dry powder), 4-di(methylamino)pyridine, DMAP, (≥99%), copper(I) bromide, CuBr, (98%), propargyl bromide (80 wt.% in toluene), N,N′-dicyclohexylcarbodiimide, DCC, (99%), methyl 3,5-dihydroxybenzoate, 3,5-MDHB, (97%), 3,5-dihydroxybenzyl alcohol, 3,5-DHBA (98%), benzyl bromide (98%), sodium ascorbate, Na-Asc (≥99%), potassium carbonate, K₂CO₃ (≥98%, powder), 18-crown-6 (99%), 2,5-dihydroxybenzoic acid, 2,5-DHBA, (98%), phenylboronic acid, PBA, (95%), 4′-bromoacetophenone, 4′-BAcP, (99%), triethylamine, TEA (99.5%), and tetrahydrofuran, THF (HPLC grade) were all purchased from Sigma-Aldrich (Miwaukee, WI, USA). Dichloro-bis(benzonitrile) palladium, Pd(PhCN)₂Cl₂, (99%) was obtained from Strem Chemicals (Newburyport, MA, USA); diethyl ether, ethyl acetate, EtOAc, hexanes, and methanol (all reagent grade) were received from Pharmco, Inc. (Brookfield, CT, USA), and dichloromethane, DCM, (spectrophotometric grade) was purchased from Spectrum/Gleason Chemicals (Syracuse, NY, USA).