The ornithine-N-oxygenase Sib2 interacts with the N-transacetylase Sib3 in the ferrichrome biosynthetic pathway.

The fission yeast produces the hydroxamate-type siderophore ferrichrome (Fc). The biosynthesis of Fc requires the Fc synthase Sib1, the ornithine-N-oxygenase Sib2, and the N-hydroxyornithine-N-transacetylase Sib3. In this study, we demonstrate the critical importance of the His residue of Sib3 in Fc production.

The flavohemoglobin Yhb1 is a new interacting partner of the heme transporter Str3.

Nitric oxide (˙NO) is a free radical that induces nitrosative stress, which can jeopardize cell viability. Yeasts have evolved diverse detoxification mechanisms to effectively counteract ˙NO-mediated cytotoxicity. One mechanism relies on the flavohemoglobin Yhb1, whereas a second one requires the S-nitrosoglutathione reductase Fmd2.

Iron homeostasis proteins Grx4 and Fra2 control activity of the Schizosaccharomyces pombe iron repressor Fep1 by facilitating [2Fe-2S] cluster removal.

The Bol2 homolog Fra2 and monothiol glutaredoxin Grx4 together play essential roles in regulating iron homeostasis in Schizosaccharomyces pombe. In vivo studies indicate that Grx4 and Fra2 act as coinhibitory partners that inactivate the transcriptional repressor Fep1 in response to iron deficiency. In Saccharomyces cerevisiae, Bol2 is known to form a [2Fe-2S]-bridged heterodimer with the monothiol Grxs Grx3 and Grx4, with the cluster ligands provided by conserved residues in Grx3/4 and Bol2 as well as GSH.

A novel role of the fission yeast sulfiredoxin Srx1 in heme acquisition.

The transporter Str3 promotes heme import in Schizosaccharomyces pombe cells that lack the heme receptor Shu1 and are deficient in heme biosynthesis. Under microaerobic conditions, the peroxiredoxin Tpx1 acts as a heme scavenger within the Str3-dependent pathway. Here, we show that Srx1, a sulfiredoxin known to interact with Tpx1, is essential for optimal growth in the presence of hemin.

Safety and efficacy of inhaled IBIO123 for mild-to-moderate COVID-19: a randomised, double-blind, dose-ascending, placebo-controlled, phase 1/2 trial.

Background: COVID-19 severity is associated with its respiratory manifestations. Neutralising antibodies against SARS-CoV-2 administered systemically have shown clinical efficacy. However, immediate and direct delivery of neutralising antibodies via inhalation might provide additional respiratory clinical benefits.