Addition/Correction pubs.acs.org/acschemicalbiology
Correction to Characterization of Choline Trimethylamine-Lyase Expands the Chemistry of Glycyl Radical Enzymes Smaranda Craciun, Jonathan A. Marks, and Emily P. Balskus* ACS Chem. Biol. 2014, 9 (7), 1408−1413, DOI: 10.1021/cb500113p S Supporting Information *
previously reported for PFL18 and class III RNR19: 8.2 ± 0.2 % for CutC (−18 aa), 8.6 ± 0.3 % for CutC (−30 aa), 9.3 ± 0.4 % CutC (−52 aa)” becomes “The extent of activation was calculated for each variant assuming a maximum of 1 radical site per CutC dimer, a result previously reported for PFL18 and class III RNR19: 16.4 ± 0.4 % for CutC (−18 aa), 17.2 ± 0.6 % for CutC (−30 aa), 18.6 ± 0.8 % CutC (−52 aa).” “The turnover number was calculated as the μmoles of product formed per second per μmol of active CutC dimer, based on a molecular mass of 182.94 kDa for CutC dimer (−52 aa), the fact that only 9.3 ± 0.4 % of CutC (−52 aa) is activated by CutD, and assuming that each dimer possesses up to 1 glycyl radical site” becomes “The turnover number was calculated as the μmoles of product formed per second per μmol of active CutC dimer, based on a molecular mass of 182.94 kDa for CutC dimer (−52 aa), the fact that only 18.6 ± 0.8 % of CutC (−52 aa) is activated by CutD, and assuming that each dimer possesses up to 1 glycyl radical site.” In Table S3, the kcat value for CutC (−52 aa) becomes 374 ± 14 s−1, and the kcat/Km value for CutC (−52 aa) becomes 1.24 μM−1 s−1. A revised Supporting Information file is attached. These corrections do not change any aspects of the interpretation of data, analysis, or the article’s conclusions. The authors apologize for this unintended error.
W
e recently realized that the EPR spectrometer we used for the measurements reported in this work was normalizing the output for receiver gain, thus rendering unnecessary any scaling that we had performed. As a result, we should not have taken into account the difference in receiver gain between the enzymatic assays and the K2(SO3)2NO and CuSO4 standards. All of the spin values we obtained via EPR measurements therefore need to be doubled, and we have corrected the following sentences in the main text to reflect this change: “The g-values and temperature dependence of this signal further confirm the presence of [4Fe−4S]+ centers in CutD, while its intensity (0.4 spins per CutD monomer) is consistent with incomplete reconstitution” becomes “The g-values and temperature dependence of this signal further confirm the presence of [4Fe−4S]+ centers in CutD, while its intensity (0.8 spins per CutD monomer) is consistent with incomplete reconstitution.” “Under these conditions we activated 9.3% of the CutC dimers” becomes “Under these conditions we activated 18.6% of the CutC dimers.” “The turnover number for activated CutC dimer (kcat of 747 ± 27 s−1) was calculated from the EPR activation measurement” becomes “The turnover number for activated CutC dimer (kcat of 374 ± 14 s−1) was calculated from the EPR activation measurement.” We have also corrected the following sentences in the Supporting Information text: “Spin concentration measurements were performed for CutC activation assays by numerically calculating the double integral of the simulated spectra and comparing the area with that of a K2(SO3)2NO standard, taking into consideration the difference in receiver gain” becomes “Spin concentration measurements were performed for CutC activation assays by numerically calculating the double integral of the simulated spectra and comparing the area with that of a K2(SO3)2NO standard, without considering the difference in receiver gain because it was already accounted for by the EPR spectrometer.” “Quantification of the signal at 9 K for each sample was performed with a Cu-EDTA standard as described in the ‘general materials and methods’, and indicated the presence of ∼0.4 spins per CutD monomer in each case” becomes “Quantification of the signal at 9 K for each sample was performed with a Cu-EDTA standard as described in the ‘general materials and methods’, and indicated the presence of ∼0.8 spins per CutD monomer in each case.” “The extent of activation was calculated for each variant assuming a maximum of 1 radical site per CutC dimer, a result © 2016 American Chemical Society
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acschembio.6b00487. (PDF)
Published: June 16, 2016 2068
DOI: 10.1021/acschembio.6b00487 ACS Chem. Biol. 2016, 11, 2068−2068
