Iskhakova Zalina I, Zhuravleva Darya E, Heim Christopher, Hartmann Marcus D, Laykov Aleksandr V, Forchhammer Karl, Kayumov Airat R
Department of Genetics, Kazan Federal University, Russia.
Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany.
FEBS J. 2022 Sep;289(17):5305-5321. doi: 10.1111/febs.16431. Epub 2022 Mar 24.
PII proteins are signal processor proteins that regulate the cellular metabolism of Bacteria, Archea and plant chloroplasts typically in response to the cellular nitrogen status. Here, we report the first biochemical characterization of a novel PII-like protein PotN from Lentilactobacillus hilgardii. PotN is encoded in an operon together with the potABCD genes, encoding the ABC transporter for spermidine/putrescine. Like canonical PII proteins, the native PotN has a trimeric structure and competitively binds ATP and ADP, but it does not bind 2-oxoglutarate. Immunoprecipitation and pull-down experiments revealed that PotN is associated in vivo with the transcriptional regulator GlnR and the beta-subunit of pyruvate/2-oxoglutarate/acetoin dehydrogenase AcoB. Moreover, in vitro assays revealed that the ATPase domain of PotA also is able to interact with PotN. Interaction analyses demonstrated that PotN preferentially associates with PotA in the ADP state, whereas it binds to GlnR at elevated ATP levels. This suggests that PotN regulates the transport of polyamines and GlnR-dependent gene expression in response to the energy availability for the cell.
PII蛋白是信号处理蛋白，通常响应细胞内的氮状态来调节细菌、古菌和植物叶绿体的细胞代谢。在此，我们报道了来自希氏扁豆乳杆菌的一种新型PII样蛋白PotN的首次生化特性分析。PotN与编码亚精胺/腐胺ABC转运蛋白的potABCD基因一起编码在一个操纵子中。与典型的PII蛋白一样，天然的PotN具有三聚体结构，能竞争性结合ATP和ADP，但不结合2-氧代戊二酸。免疫沉淀和下拉实验表明，PotN在体内与转录调节因子GlnR以及丙酮酸/2-氧代戊二酸/乙偶姻脱氢酶的β亚基AcoB相关联。此外，体外实验表明PotA的ATP酶结构域也能够与PotN相互作用。相互作用分析表明，PotN在ADP状态下优先与PotA结合，而在ATP水平升高时与GlnR结合。这表明PotN响应细胞的能量可用性来调节多胺的转运和GlnR依赖性基因表达。
