Identification of an Intermediate Form of Ferredoxin That Binds Only Iron Suggests That Conversion to Holo-Ferredoxin Is Independent of the ISC System in Escherichia coli.

ABSTRACT: Escherichia coli [2Fe-2S]-ferredoxin and other ISC proteins encoded by the iscRSUA-hscBA-fdx-iscX (isc) operon are responsible for the assembly of iron-sulfur clusters. It is proposed that ferredoxin (Fdx) donates electrons from its reduced [2Fe-2S] center to iron-sulfur cluster biogenesis reactions. However, the underlying mechanisms of the [2Fe-2S] cluster assembly in Fdx remain elusive. Here, we report that Fdx preferentially binds iron, but not the [2Fe-2S] cluster, under cold stress conditions (≤16°C). The iron binding in Fdx is characterized by a unique absorption peak at 320 nm based on UV-visible spectroscopy. In addition, the iron-binding form of Fdx could be converted to the [2Fe-2S] cluster-bound form after transferring cold-stressed cells to normal cultivation temperatures abov

SUBMITTER: Ren X 

PROVIDER: S-EPMC8117754 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature