The presence of two different clusters in the active enzyme, as well as the observation of [2Fe 2S] cluster degradation during turnover, led to the proposal that the [2Fe 2S] cluster was the source of sulfur in biotin biosynthesis.
Shareholder monopolization was related positively to turnover clustering.
TMT members' average pay level was related negatively to top management team's turnover clustering.
Furthermore, changes in several temporal properties can alleviate the impact on species viability, for example, by reducing clustering in habitat turnover events.
Shen et al., 2011b 19 ST companies and 19 non-ST companies from 2008 to 2009 Top management team Financial distress, shareholder monopolization, TMT members' average pay levels Logistic regression Financial distress and shareholder monopolization related positively to top management team's turnover clustering.
Generation of variants in which each of these cysteinyl residues are changed to alanines revealed that while variant C69A behaved like wild-type protein, the C235A variant produced less soluble protein with bound Fe S clusters but displayed turnover activity ≤10% of wild type; the remaining mutations at positions Cys169, Cys187, and Cys232 yielded insoluble proteins.
The structure, along with mechanistic and spectroscopic studies similar to those described for MiaB, provide strong evidence that the second cluster remains intact during turnover.
Theoretically, we would predict that the stoichiometry of 3Fe-clusters and monothiolated species would be identical if one cluster were sacrificed during turnover and that 0.9 [4Fe–4S] clusters (based on a total of 1.8 [4Fe–4S] clusters in the starting enzyme) and 0.9 3Fe-clusters would remain.
The coupled spectroscopic and biochemical studies of Jarrett and co-workers provided the first clear evidence that both [4Fe 4S] and [2Fe 2S] clusters were present in active forms of biotin synthase, and that while the [2Fe 2S] cluster was degraded during turnover, the [4Fe 4S] was stable (section 4.1.2).
This high turnover of clusters allows for high temporal precision.
