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Bakteryjne strategie wykorzystania jonów metali – kulisy chemii koordynacyjnej

Piasta Karolina, Mular Andrzej, Rola Anna, Dzyhovskyi Valentyn, Potok Paulina, Orzeł Bartosz, Potocki Sławomir, Stokowa-Sołtys Kamila, Kozłowski Henryk, Gumienna-Kontecka Elżbieta

Wiadomości Chemiczne

2022

[Z] 76, 5-6

287-308

In the Biological Inorganic Chemistry Group we are inspired to better understand metal ions acquisition and homeostasis in pathogenic bacteria, and in this review we present three different approaches to the role of these processes. The growing importance of a full understanding of the iron transport system in pathogens prompted us to study synthetic analogs of siderophores, used as structural probes in the process of iron uptake by microorganisms. The ferrichrome biomimetic analogs allowed efficient Fe(III) chelation under biological conditions and were recognized better by P. putida. than E. coli, suggesting differences in uptake mechanisms. Addition of a fluorescent probe to the compound allowed to track biological fate of studied complexes [1, 2]. Biomimetics of ferrioxamine E revealed their potential as radioactive 68Ga(III)-based probes [3], and studies of Zr(IV) complexes permitted to explain the in vivo behavior of desferrioxamine B as 89Zr(IV) radionuclide carrier [4], as well as design better chelators for this metal ion [5]. One of the possible mammalian immune system responsesto mycobacterial infection is the increase of Zn(II) concentration in phagosomes to a toxic level [6-8]. The mycobacterial SmtB protein is a transcription regulator that in the presence of high concentrations of metals, dissociates from DNA and activates the expression of metal efflux proteins. We focused on α5 Zn(II) binding domains of SmtB/BigR4 proteins [9], looking at the coordination modes and thermodynamics of their Zn(II) and Ni(II) complexes. The study points out the specificity of metal-ligand interactions and the effect of mutations on the coordination properties of studied systems. The project can be considered as an introduction to the new strategies in tuberculosis treatment based on Zn(II)/Ni(II)-sensitive mechanisms. F. nucleatum is an anaerobic bacteria present in the plaque. It leads not only to periodontal diseases but also, angina, purulent inflammation of the lung tissue or reproductive organs [10]. Moreover, F. nucleatum promotes colon cancer growth [11]. This bacteria strain promotes inflammation and tumorigenesis by modulating the tumor immune microenvironment [12, 13]. Microbial pathogens drive tumorigenesis in 15–20% of cancer cases [14]. However, not only microorganisms are considered a major risk factor, but also metal ions play an important role in tumor promotion [15, 16]. Therefore, our primary research goal is to investigate the effect of metal ions coordination on the activity of outer-membrane proteins from F. nucleatum and to answer whether these proteins increase the prooxidative activity of Cu(II) and Fe(II) ions [16-18].

Białka uczestniczące w transporcie jonów żelaza(II) w bakteriach gram-ujemnych

Kierpiec Karolina, Stokowa-Sołtys Kamila

Wiadomości Chemiczne

2021

[Z] 75, 3-4

375--394

Continuous increase in the number of multidrug-resistant strains forces us to look for drugs with completely new mode of action. One of the bacterial property determining the pathogenicity of these microorganisms is their ability to obtain iron. Because in the living environment of these single-celled individuals, its concentration is much lower than this necessary for their growth. For this reason, bacteria created various type of iron aquisition systems, including the Feo system, which mechanism of Fe2+ ion uptake is not fully understood, and protein from the Hmu family belonging to ABC transporters. The Feo transport system is one of the most common systems that is exclusively responsible for importing Fe2+ ions. It consists of three proteins: FeoA, FeoB and FeoC. FeoB is a transmembrane protein that is believed to play a key role in the mechanism of Fe2+ ion uptake. The other two components are cytoplasmic proteins. Both, FeoA and FeoC, are cytoplasmic proteins resembling the construction of transcription regulators. ABC transporters play an equally important role in maintaining iron homeostasis. These include proteins from Hmu family. HmuUV complex catalyses the import of these ions in hem iron form. The structure of this complex consists of TMD dimer (HmuU) and NBD dimer (HmuV). The HmuU is considered to be a permease - just like the FeoB described earlier while HmuV is the ATP binding protein.