The Transcriptional Repressor PerR Senses Sulfane Sulfur by Cysteine Persulfidation at the Structural Zn2+ Site in Synechococcus sp. PCC7002

Abstract

Cyanobacteria can perform both anoxygenic and oxygenic photosynthesis, a characteristic which ensured that these organisms were crucial in the evolution of the early Earth and the biosphere. Reactive oxygen species (ROS) produced in oxygenic photosynthesis and reactive sulfur species (RSS) produced in anoxygenic photosynthesis are closely related to intracellular redox equilibrium. ROS comprise superoxide anion (O2●−), hydrogen peroxide (H2O2), and hydroxyl radicals (●OH). RSS comprise H2S and sulfane sulfur (persulfide, polysulfide, and S8). Although the sensing mechanism for ROS in cyanobacteria has been explored, that of RSS has not been elucidated. Here, we studied the function of the transcriptional repressor PerR in RSS sensing in Synechococcus sp. PCC7002 (PCC7002). PerR was previously reported to sense ROS; however, our results revealed that it also participated in RSS sensing. PerR repressed the expression of prxI and downregulated the tolerance of PCC7002 to polysulfide (H2Sn). The reporter system indicated that PerR sensed H2Sn. Cys121 of the Cys4:Zn2+ site, which contains four cysteines (Cys121, Cys124, Cys160, and Cys163) bound to one zinc atom, could be modified by H2Sn to Cys121-SSH, as a result of which the zinc atom was released from the site. Moreover, Cys19 could also be modified by polysulfide to Cys19-SSH. Thus, our results reveal that PerR, a representative of the Cys4 zinc finger proteins, senses H2Sn. Our findings provide a new perspective to explore the adaptation strategy of cyanobacteria in Proterozoic and contemporary sulfurization oceans.

A cascade of sulfur transferases delivers sulfur to the sulfur-oxidizing heterodisulfide reductase-like complex

“…denitrificans possesses two candidate transporters (SoxT1A and SoxT1B, Figure 1) encoded in close proximity to the genes encoding Sox proteins that are involved in the initial steps of thiosulfate oxidation and the genes for the cytoplasmic sHdr system. (43,50) However, evidence supporting the proposed sulfur transport has yet to be presented. Related transporters are not encoded in Aq.…”

“…The proteins were then transferred to salt-free 50 mM Tris-HCl buffer (pH 7.5) or to 20 mM Tris-HCl buffer pH 7.4 for AqTusA and stored at −70°C. Size exclusion chromatography on HiLoad 16/60 Superdex™ 75 (Cytiva, Freiburg, Germany) was performed as described in Li et al (50)…”

“…The polysulfide stock solution needed for these experiments was prepared, diluted and used as previously described. (50,55) For sulfur transfer experiments, 1.5 nmol of the putative sulfur-donating protein were incubated with 0.5 mM polysulfide for 30 minutes at room temperature in 20 µl 50 mM Tris–HCl pH 7,5. Acceptor proteins were reduced with 1 mM DTT under the same conditions.…”

L‐Glutamine Substantially Improves 5‐Fluorouracil‐Induced Intestinal Mucositis by Modulating Gut Microbiota and Maintaining the Integrity of the Gut Barrier in Mice

“…These findings indicate that glutamine, at a suitable dosage, was capable of enhancing the Nrf2/HO-1 pathway, which is essential for cellular defense against oxidative stress and the promotion of gut health. [56]…”

Zinc Finger Proteins in the War on Gastric Cancer: Molecular Mechanism and Clinical Potential

“…Initially discovered in Xenopus oocytes in 1983 by Miller to describe the predicted finger-like profile of transcription factor IIIA (TFIIIA), this family has now been expanded with continuously discovered paralogous proteins [22]. Based on their conserved domains, ZFPs can be mainly divided into three categories, which are Cys2His2 (C2H2)type, Cys4 (C4)-type and Cys6 (C6)-type [23]. Among these, the C2H2-type zinc finger is the most widely distributed of the entire zinc finger motif classes [24].…”