Figure 4
Plots of Alexa488 hydroxyl radical dose-response rates obtained for radiolytic degradation of 4.0 µM Alexa488 in PBS pH 7.4 buffer versus concentration of buffer constituents and other organic compounds commonly used in studying biomolecules, organized by compound class. The lines show fits to either single or double exponential functions to highlight phase behavior (Table S2); some compounds (HEPES, NaHCO3, NG) show poor fits to these functions over the concentration range studied and so their fit lines are not shown. A dot–dash line is shown to indicate the Alexa488 hydroxyl radical dose-response rate of 180 s−1 measured for PBS pH 7.4 buffer under the conditions used for this study. For the detergent experiment in (c) the concentrations span the typical concentrations employed for biomolecular purification, which typically are two to three times the critical micelle concentration (CMC); the CMC for the detergents studied: DDM [0.0087%(w/v)], LMNG [0.001%(w/v)] and NG [0.2%(w/v)]. Abbreviations/chemical names: NH4CH3CO2, ammonium acetate; NaHCO3, sodium bicarbonate; tris, tris(hydroxymethyl)aminomethane; MES, 2-(N-morpholino)ethanesulfonic acid; HEPES, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; NG, n-nonyl-β-D-glucopyranoside; LMNG, lauryl maltose-neopentyl glycol; DDM, n-dodecyl-β-D-maltopyranoside; DTT, dithiothreitol; TCEP, tris(2-carboxyethyl)phosphine; BME, β-mercaptoethanol; Gdn–HCl, guanidinium hydrochloride; ACN, acetonitrile; DMSO, dimethyl sulfoxide; MeOH, methanol; dNTP, deoxyribonucleotide triphosphate; ATP, adenosine triphosphate; and GDP, guanosine diphosphate. |