Table 4.
Analysis of Mössbauer resonances as a percentage of total Fe during [2Fe-2S]2+/[4Fe-4S]2+ cluster conversions on NifIscA. Values in parentheses are estimated uncertainties for the last significant digits.
| Sample | [2Fe-2S]2+ | [4Fe-4S]2+ | FeII | remaining Fea |
|---|---|---|---|---|
| Reconstituted [2Fe-2S]2+ NifIscA (Sample A) | 100 | – | – | – |
| Sample A treated with 2 mM DTT for 1 min | 34 (4) | 43 (4) | 10 (2) | 13 (2) |
| Sample A treated with 2 mM DTT for 15 min | 16 (3) | 53 (5) | 18 (3) | 13 (2) |
| Sample A treated with 2 mM DTT for 15 min and air for 5 min | 60 (5) | 15 (3) | – | 25 (3) |
a
The remaining Fe is primarily in the form a S = 1/2 [2Fe-2S]+ cluster for the samples treated with DTT for 1 min and 15 min and in the form of S = 3/2 Fe(III)-bound NifIscA for the sample treated with DTT and then exposed to air (see text for details).