English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The scaffold protein for iron-sulfur cluster assembly, apo-IscU, populates two interconverting conformational states, one disordered (D) and one structured (S) as revealed by extensive NMR assignments. At pH 8 and 25 °C, approximately 70% of the protein is S, and the lifetimes of the states are 1.3 s (S) and 0.50 s (D). Zn(II) and Fe(II) each bind and stabilize structured (S-like) states. Single amino acid substitutions at conserved residues were found that shift the equilibrium toward either the S or the D state. Cluster assembly takes place in the complex between IscU and the cysteine desulfurase, IscS, and our NMR studies demonstrate that IscS binds preferentially the D form of apo-IscU. The addition of 10% IscS to IscU was found to greatly increase H/D exchange at protected amides of IscU, to increase the rate of the S → D reaction, and to decrease the rate of the D → S reaction. In the saturated IscU:IscS complex, IscU is largely disordered. In vitro cluster assembly reactions provided evidence for the functional importance of the S⇆D equilibrium. IscU variants that favor the S state were found to undergo a lag phase, not observed with the wild type, that delayed cluster assembly; variants that favor the D state were found to assemble less stable clusters at an intermediate rate without the lag. It appears that IscU has evolved to exist in a disordered conformational state that is the initial substrate for the desulfurase and to convert to a structured state that stabilizes the cluster once it is assembled.

Disordered form of the scaffold protein IscU is the substrate for iron-sulfur cluster assembly on cysteine desulfurase