0000000001317647
AUTHOR
Danuta Witkowska
Medical Chemistry Group
The Medical Chemistry Group is focused on medicinal and bioinorganic chemistry, mainly related to peptides and proteins. In general, projects on the interaction of biologically important macromolecules with other molecules or metal ions are underway. Two National Science Centre grants are being realized by group members. One of them is about hot topic – SARS-Cov2/virus protein interaction with human receptor. The second is about interaction of iron ions with small heat shock protein, which is involved in ferroptosis (programmed cell death dependent on iron). Cooperation includes research centers in Poland and abroad, e.g. University of Wroclaw and USA, but also other faculties of University…
A Comparative Study on Nickel Binding to Hpn-like Polypeptides from Two Helicobacter pylori Strains
Combined potentiometric titration and isothermal titration calorimetry (ITC) methods were used to study the interactions of nickel(II) ions with the N-terminal fragments and histidine-rich fragments of Hpn-like protein from two Helicobacter pylori strains (11637 and 26695). The ITC measurements were performed at various temperatures and buffers in order to extract proton-independent reaction enthalpies of nickel binding to each of the studied protein fragments. We bring up the problem of ITC results of nickel binding to the Hpn-like protein being not always compatible with those from potentiometry and MS regarding the stoichiometry and affinity. The roles of the ATCUN motif and multiple His…
Analysis of substrate binding in individual active sites of bifunctional human ATIC
Aminoimidazolecarboxamide ribonucleotide formyl transferase (AICARFT): Inosine monophosphate cyclohydrolase (IMPCH, collectively called ATIC) is a bifunctional enzyme that catalyses the penultimate and final steps in the purine de novo biosynthesis pathway. The bifunctional protein is dimeric and each monomer contains two different active sites both of which are capable of binding nucleotide substrates, this means to a potential total of four distinct binding events might be observed. Within this work we used a combination of site-directed and truncation mutants of ATIC to independently investigate the binding at these two sites using calorimetry. A single S10W mutation is sufficient to blo…
A novel approach for obtaining α,β-diaminophosphonates bearing structurally diverse side chains and their interactions with transition metal ions studied by ITC
Aminophosphonates are an important group of building blocks in medicinal and pharmaceutical chemistry. Novel representatives of this class of compounds containing nontypical side chains are still needed. The aza-Michael-type addition of amines to phosphonodehydroalanine derivatives provides a simple and effective approach for synthesizing N′-substituted α,β-diaminoethylphosphonates and thus affords general access to aminophosphonates bearing structurally diverse side chains. Thermodynamic analysis of the chosen aminophosphonates at physiological pH proves that they serve as potent chelators for copper(II) ions and moderate chelators for nickel(II) ions.
Zn(II)-alloferon complexes - Similar sequence, different coordination modes, no antibacterial activity.
Often, in the search for a highly defined scientific phenomenon, a different one becomes apparent. This was also the case of this work, in the scope of which we planned to search for metal-enhanced, novel antibacterial/ antifungal compounds. Instead, we denied the existence of such and revealed the details of the bioinorganic chemistry of Zn(II)-alloferon complexes. Zinc(II) complexes of alloferon 1 and 2, ligands with a sequential difference of one amino acid only, show a substantially different coordination pattern at physiological pH. In the case of Zn(II)-alloferon 1 species, a histamine-like binding mode is observed (N-terminal amine and imidazole of His-1) and the coordination sphere …
Thermodynamic surprises of Cu(II)–amylin analogue complexes in membrane mimicking solutions
AbstractMembrane environment often has an important effect on the structure, and therefore also on the coordination mode of biologically relevant metal ions. This is also true in the case of Cu(II) coordination to amylin analogues—rat amylin, amylin1–19, pramlintide and Ac-pramlintide, which offer N-terminal amine groups and/or histidine imidazoles as copper(II) anchoring sites. Complex stabilities are comparable, with the exception of the very stable Cu(II)–amylin1–19, which proves that the presence of the amylin C-terminus lowers its affinity for copper(II); although not directly involved, its appropriate arrangement sterically prevents early metal binding. Most interestingly, in membrane…
An adventive Panaeolus antillarum in Poland (Basidiomycota, Agaricales) with notes on its taxonomy, geographical distribution, and ecology
Abstract Coprophilous fungus, Panaeolus antillarum rarely recorded in Europe, is reported here for the first time from the Augustow Plane, north-eastern Poland. This thermophilic species was found outdoors in August on horse dung mixed with straw. A chemical analysis did not confirm the presence of the psychoactive alkaloids in collected material. A complete description and illustration of the species based on Polish specimens are presented and notes on its taxonomy, ecology, world distribution and comparison with similar taxa — P. semiovatus var. semiovatus, P. semiovatus var. phalaenarum, and others are also provided.
Copper(II)-Binding Induces a Unique Polyproline Type II Helical Structure within the Ion-Binding Segment in the Intrinsically Disordered F-Domain of Ecdysteroid Receptor from Aedes aegypti
Reproduction of the dominant vector of Zika and dengue diseases, Aedes aegypti mosquito, is controlled by an active heterodimer complex composed of the 20-hydroxyecdysone receptor (EcR) and ultraspiracle protein. Although A. aegypti EcR shares the structural and functional organization with other nuclear receptors, its C-terminus has an additional long F domain (AaFEcR). Recently, we showed that the full length AaFEcR is intrinsically disordered with the ability to specifically bind divalent metal ions. Here, we describe the details of the exhaustive structural and thermodynamic properties of Zn2+- and Cu2+-complexes with the AaFEcR domain, based on peptide models of its two putative metal …
Biophysical approaches for the study of metal-protein interactions
Protein-protein interactions play important roles for a variety of cell functions, often involving metal ions; in fact, metal-ion binding mediates and regulates the activity of a wide range of biomolecules. Enlightening all of the specific features of metal-protein and metal-mediated protein-protein interactions can be a very challenging task; a detailed knowledge of the thermodynamic and spectroscopic parameters and the structural changes of the protein is normally required. For this purpose, many experimental techniques are employed, embracing all fields of Analytical and Bioinorganic Chemistry. In addition, the use of peptide models, reproducing the primary sequence of the metal-binding …
Zn-Enhanced Asp-Rich Antimicrobial Peptides N-Terminal Coordination by Zn(II) and Cu(II), Which Distinguishes Cu(II) Binding to Different Peptides
The antimicrobial activity of surfactant-associated anionic peptides (SAAPs), which are isolated from the ovine pulmonary surfactant and are selective against the ovine pathogen Mannheimia haemolytica, is strongly enhanced in the presence of Zn(II) ions. Both calorimetry and ITC measurements show that the unique Asp-only peptide SAAP3 (DDDDDDD) and its analogs SAAP2 (GDDDDDD) and SAAP6 (GADDDDD) have a similar micromolar affinity for Zn(II), which binds to the N-terminal amine and Asp carboxylates in a net entropically-driven process. All three peptides also bind Cu(II) with a net entropically-driven process but with higher affinity than they bind Zn(II) and coordination that involves the N…
Mass Spectrometry and Structural Biology Techniques in the Studies on the Coronavirus-Receptor Interaction
Mass spectrometry and some other biophysical methods, have made substantial contributions to the studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human proteins interactions. The most interesting feature of SARS-CoV-2 seems to be the structure of its spike (S) protein and its interaction with the human cell receptor. Mass spectrometry of spike S protein revealed how the glycoforms are distributed across the S protein surface. X-ray crystallography and cryo-electron microscopy made huge impact on the studies on the S protein and ACE2 receptor protein interaction, by elucidating the three-dimensional structures of these proteins and their conformational changes. The…
SARS-CoV-2 and its impact on the cardiovascular and digestive systems – The interplay between new virus variants and human cells
Since infection with the novel coronavirus SARS-CoV-2 first emerged in Wuhan, China, in December 2019,the world has been battling the pandemic COVID-19. Patients of all ages and genders are now becoming infected with the new coronavirus variant (Omicron) worldwide, and its subvariants continue to pose a threat to health and life. This article provides a literature review of cardiovascular and gastrointestinal complications resulting from SARS-CoV-2 infection. COVID-19 primarily caused respiratory symptoms, but complications can affect many vital organs. SARS-CoV-2 binds to a human cell receptor (angiotensin-converting enzyme 2 – ACE2) that is predominantly expressed primarily in the heart a…
General Aspects of Metal Ions as Signaling Agents in Health and Disease
This review focuses on the current knowledge on the involvement of metal ions in signaling processes within the cell, in both physiological and pathological conditions. The first section is devoted to the recent discoveries on magnesium and calcium-dependent signal transduction—the most recognized signaling agents among metals. The following sections then describe signaling pathways where zinc, copper, and iron play a key role. There are many systems in which changes in intra- and extra-cellular zinc and copper concentrations have been linked to important downstream events, especially in nervous signal transduction. Iron signaling is mostly related with its homeostasis. However, it is also …
Heavy Metals and Human Health: Possible Exposure Pathways and the Competition for Protein Binding Sites
Heavy metals enter the human body through the gastrointestinal tract, skin, or via inhalation. Toxic metals have proven to be a major threat to human health, mostly because of their ability to cause membrane and DNA damage, and to perturb protein function and enzyme activity. These metals disturb native proteins’ functions by binding to free thiols or other functional groups, catalyzing the oxidation of amino acid side chains, perturbing protein folding, and/or displacing essential metal ions in enzymes. The review shows the physiological and biochemical effects of selected toxic metals interactions with proteins and enzymes. As environmental contamination by heavy metals is one of the most…
Bioactive Alkaloids of Hallucinogenic Mushrooms
Abstract The aim of our chapter is to review recent developments in a group of medicinally important natural products–alkaloids, with reference to the structure–activity studies in respect of certain diseases. Alkaloids covered by our review come from mushrooms called “hallucinogenic.” Hallucinogenic compounds have been chemically identified in mushrooms belonging to various genera, e.g., Agrocybe, Amanita, Conocybe, Galerina, Gymnopilus, Hypholoma, Inocybe, Panaeolus, Psilocybe, Pholiotina, Pluteus, and Weraroa [J.W. Allen, Ethnomycol. J. Sacred Mushroom Stud. 9 (2012) 130–175]. One of the largest classes of alkaloids is indole alkaloids. Indoles are probably the most widely distributed he…
CCDC 1935968: Experimental Crystal Structure Determination
Related Article: Paweł Lenartowicz, Danuta Witkowska, Beata Żyszka-Haberecht, Błażej Dziuk, Krzysztof Ejsmont, Jolanta Świątek-Kozłowska, Paweł Kafarski|2020|RSC Advances|10|24045|doi:10.1039/D0RA03764H
CCDC 1935969: Experimental Crystal Structure Determination
Related Article: Paweł Lenartowicz, Danuta Witkowska, Beata Żyszka-Haberecht, Błażej Dziuk, Krzysztof Ejsmont, Jolanta Świątek-Kozłowska, Paweł Kafarski|2020|RSC Advances|10|24045|doi:10.1039/D0RA03764H