Niemand Wolhuter Nandi, Ngakane Lerato, de Wet Timothy J, Warren Robin M, Williams Monique J
NRF/DSI Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa.
SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa.
Microorganisms. 2023 Jun 14;11(6):1573. doi: 10.3390/microorganisms11061573.
A-type carrier (ATC) proteins are proposed to function in the biogenesis of Fe-S clusters, although their exact role remains controversial. The genome of encodes a single ATC protein, MSMEG_4272, which belongs to the HesB/YadR/YfhF family of proteins. Attempts to generate an _ deletion mutant by two-step allelic exchange were unsuccessful, suggesting that the gene is essential for in vitro growth. CRISPRi-mediated transcriptional knock-down of resulted in a growth defect under standard culture conditions, which was exacerbated in mineral-defined media. The knockdown strain displayed reduced intracellular iron levels under iron-replete conditions and increased susceptibility to clofazimine, 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), and isoniazid, while the activity of the Fe-S containing enzymes, succinate dehydrogenase, and aconitase were not affected. This study suggests that MSMEG_4272 plays a role in the regulation of intracellular iron levels and is required for in vitro growth of , particularly during exponential growth.
A型载体（ATC）蛋白被认为在铁硫簇的生物合成中发挥作用，尽管它们的确切作用仍存在争议。结核分枝杆菌的基因组编码一种单一的ATC蛋白，MSMEG_4272，它属于HesB/YadR/YfhF蛋白家族。通过两步等位基因交换产生结核分枝杆菌缺失突变体的尝试未成功，这表明该基因对于体外生长至关重要。CRISPRi介导的结核分枝杆菌转录敲低导致在标准培养条件下生长缺陷，在矿物限定培养基中这种缺陷加剧。敲低菌株在铁充足条件下细胞内铁水平降低，对氯法齐明、2,3 - 二甲氧基 - 1,4 - 萘醌（DMNQ）和异烟肼的敏感性增加，而含铁硫酶、琥珀酸脱氢酶和乌头酸酶的活性未受影响。这项研究表明，MSMEG_4272在细胞内铁水平的调节中起作用，并且是结核分枝杆菌体外生长所必需的，特别是在指数生长期。
