Staphylococcus aureus SufT: an essential iron‐sulphur cluster assembly factor in cells experiencing a high‐demand for lipoic acid

Abstract

Summary S. aureus SufT is composed solely of the domain of unknown function 59 (DUF59) and has a role in the maturation of iron-sulfur (Fe-S) proteins. We report that SufT is essential for S. aureus when growth is heavily reliant upon lipoamide-utilizing enzymes, but dispensable when this reliance is decreased. LipA requires Fe-S clusters for lipoic acid (LA) synthesis and a ΔsufT strain had phenotypes suggestive of decreased LA production and decreased activities of lipoamide-requiring enzymes. Fermentative growth, a null clpC allele, or decreased flux through the TCA cycle diminished the demand for LA and rendered SufT non-essential. Abundance of the Fe-S cluster carrier Nfu was increased in a ΔclpC strain and a null clpC allele was unable to suppress the LA requirement of a ΔsufT Δnfu strain. Over-expression of nfu suppressed the LA requirement of the ΔsufT strain. We propose a model wherein SufT, and by extension the DUF59, is essential for the maturation of holo-LipA in S. aureus cells experiencing a high demand for lipoamide-dependent enzymes. The findings presented suggest that the demand for products of Fe-S enzymes is a factor governing the usage of one Fe-S cluster assembly factor over another in the maturation of apo-proteins.

The Suf Iron-Sulfur Cluster Biosynthetic System Is Essential in Staphylococcus aureus, and Decreased Suf Function Results in Global Metabolic Defects and Reduced Survival in Human Neutrophils

“…The chemically defined minimal medium was described previously (63) and where noted was supplemented with 0.5 g ml Ϫ1 lipoic acid. S. aureus strains cultured in TSB were grown at 37°C with shaking at 200 rpm in 10-ml culture tubes containing 1 ml of liquid medium unless otherwise stated.…”

SaeRS Is Responsive to Cellular Respiratory Status and Regulates Fermentative Biofilm Formation in Staphylococcus aureus

“…All plasmids utilized are listed in Table 2. The pCM28_saePQRS plasmid, containing saePQRS under the transcriptional control of the native promoter, was constructed using yeast recombinational cloning as previously described (59)(60)(61). The saePQRS alleles and the upstream promoter region were amplified from the LAC chromosome.…”

A Small-Molecule Inhibitor of Iron-Sulfur Cluster Assembly Uncovers a Link between Virulence Regulation and Metabolism in Staphylococcus aureus

“…The transcription of sufC is increased under growth conditions that impose an increased demand for Fe-S cluster biogenesis (Mashruwala et al, 2015, 2016b). SufT is a Fe-S maturation factor selectively used under growth conditions that impose an increased demand for Fe-S cluster biogenesis and the transcription of sufT increases under such conditions (Mashruwala et al, 2015, 2016a, 2016b). The abundance of SufT increases in cells toxified by ’882, further emphasizing that intoxication by ’882 results in an increased need for the Fe-S cluster assembly machinery.…”