Karolina Bossak

Institute of Biochemistry and Biophysics Polish Academy of Sciences · Department of Biophysics

Human serum albumin (HSA) and the growth factor glycyl-l-histidyl-l-lysine (GHK) bind Cu2+ as part of their normal functions. GHK is found at its highest concentration in the albumin-rich fraction of plasma, leading to speculation that HSA and GHK form a ternary Cu2+ complex. Although preliminary evidence was presented 40 years ago, the structure a...

The Aβ 4−42 peptide is a major beta-amyloid species in the human brain, forming toxic aggregates related to Alzheimer's Disease. It also strongly chelates Cu(II) at the N-terminal Phe-Arg-His ATCUN motif, as demonstrated in Aβ 4−16 and Aβ 4−9 model peptides. The resulting complex resists ROS generation and exchange processes and may help protect sy...

The Aβ5–x peptides (x = 38, 40, 42) are minor Aβ species in normal brains but elevated upon the application of inhibitors of Aβ processing enzymes. They are interesting from the point of view of coordination chemistry for the presence of an Arg-His metal binding sequence at their N-terminus capable of forming a 3-nitrogen (3N) three-coordinate chel...

The peptide Gly–His–Lys (GHK, the natural wound healing factor) and urocanic acid (UCA, a constituent of the natural moisturizing factor) coexist in the human body, e.g., in the skin. They also share some biological activities, e.g., both modulate the immune and nervous systems. Interestingly, they have never been considered to function mutually. W...

The tripeptide NH2–Gly–His–Lys–COOH (GHK), cis-urocanic acid (cis-UCA) and Cu(II) ions are physiological constituents of the human body and they co-occur (e.g., in the skin and the plasma). While GHK is known as Cu(II)-binding molecule, we found that urocanic acid also coordinates Cu(II) ions. Furthermore, both ligands create ternary Cu(II) complex...

Bioanorganische Chemie W. Bal et al. demonstrieren auf S. 11330, dass die Bindung von CuII an GGH‐Peptid, ein prototypischesATCUN/NTS‐Motiv, über partiell koordinierte Spezies verläuft. Eine 2N‐koordinierte Spezies mit CuII/CuI‐Redoxaktivität ist die lange gesuchte reaktive Zwischenstufe beim extrazellulären Kupfertransport.

Bioinorganic Chemistry W. Bal et al. demonstrate in their Communication on page 11234 that CuII binding to GGH peptide proceeds via partially coordinated species. A 2N‐coordinated species with CuII/CuI redox activity is the long‐sought reactive intermediate for extracellular copper delivery.

The amino‐terminal copper and nickel/N‐terminal site (ATCUN/NTS) present in proteins and bioactive peptides exhibits high affinity towards Cu II ions and have been implicated in human copper physiology. Little is known, however, about the rate and exact mechanism of formation of such complexes. We used the stopped‐flow and microsecond freeze‐hyperq...

ATCUN/NTS motifs participate in physiological CuII exchange. Using kinetic methods, spectroscopy, and electrochemistry, it was demonstrated that CuII binding to GGH, an ATCUN/NTS representative, proceeds via partially coordinated species. The 2N‐coordinated complex with t 1/2≈100 ms (pH 6.0) and CuII/CuI redox activity is the long‐sought reactive i...

Copper(II) binding properties of Saccharomyces cerevisiae pheromone (α-factor) analogues, namely WHWSKNR-am, FHWSKNR-am and WHFSKNR-am amino acid sequences, were studied using voltammetry techniques, fluorescence and UV–Vis spectroscopy. Despite the same 3N binding mode attributed to XHZ-type oligopeptides, the obtained results demonstrated high de...

Model peptides relevant to hCtr1 transchelate Cu I from the anti-tumour [CuI(PTA) 4 ] ⁺ complex before metal internalization into tumor cells. ESI(+)MS experiments corroborated by DFT calculations indicate that tetracoordinated-Cu II and linear-Cu I arrangements...

The apparent affinity of human serum albumin (HSA) for divalent copper has long been the subject of great interest, due to its presumed role as the major Cu2+ -binding ligand in blood and cerebrospinal fluid. Using a combination of electronic absorption, circular dichroism and room-temperature electron paramagnetic resonance spectroscopies, togethe...

Copper(II) forms well-known and stable complexes with peptides having histidine at position 2 (Xxx-His) or 3 (Xxx-Zzz-His). Their properties differ considerably due to the histidine positioning. Here we report that...

The catabolism of β-amyloid (Aβ) is carried out by numerous endopeptidases including neprilysin, which hydrolyzes peptide bonds preceding positions 4, 10, and 12 to yield Aβ4-9 and a minor Aβ12-x species. Alternative processing of the amyloid precursor protein by β-secretase also generates the Aβ11-x species. All these peptides contain a Xxx-Yyy-Hi...

Human cells acquire copper primarily via the copper transporter 1 protein, hCtr1. We demonstrate that at extracellular pH 7.4 Cu(II) is bound to the model peptide hCtr1_1-14 via an ATCUN motif and such complexes are strong enough to collect Cu(II) from albumin, supporting the potential physiological role of Cu(II) binding to hCtr1.

Engineering a copper site into proteins or peptides can add new functions to them. Two very small and relatively strong CuII binding sites consist of two or three amino acids at the N‐terminus. They can be easily added chemically or recombinantly. Such constructs have been used in metalloprotein engineering for different approaches in chemistry, bi...

Copper Transporter 1 (CTR1) is a homotrimeric membrane protein providing the main route of copper transport into eukaryotic cells from the extracellular milieu. Its N-terminal extracellular domain, rich in His and Met residues, is considered responsible for directing copper into the transmembrane channel. Most of vertebrate CTR1 proteins contain th...

Peptides and proteins with N-terminal amino acid sequences NH2-Xxx-His (XH) and NH2-Xxx-Zzz-His (XZH) form well established high affinity CuII-complexes. Key examples are Asp-Ala-His (in serum albumin) and Gly-His-Lys, the wound healing factor. This opens a straightforward way to add a high affinity CuII-binding site to almost any peptide or protei...

Peptides and proteins with the N-terminal motifs NH2-Xxx-His and NH2-Xxx-Zzz-His form well-established copper(II) complexes with different coordination modes. Peptides with the sequence NH2-Xxx-His-His contain both motifs. This work shows that NH2-Ala-His-His indeed can access both Cu(II) coordination types in a pH dependent manner. Changes in the...

α-Factor-1 (WHWLQLKPGQPMY), a peptidic pheromone of Saccharomyces cerevisiae yeast, contains a XHX type copper(II) binding N-terminal site. Using a soluble analogue, WHWSKNR-amide, we demonstrated that the W(1)H(2)W(3) site alone binds copper(II) with a Kd value of 0.18 pM at pH 7.4 and also binds imidazole (Im) in a ternary complex (Kd of 1 mM at...

Poly(ADP-ribose) polymerase 1 (PARP-1) is a key eukaryotic enzyme, catalyzing the NAD+ dependent poly(ADP-ribosyl)ation of protein substrates, crucial for major DNA repair pathways, and involved in other fundamental cellular processes, such as transcription, cell cycle control, and apoptosis. Its ability to bind DNA depends on two CCHC zinc finger...

Nickel is harmful for humans, but molecular mechanisms of its toxicity are far from being fully elucidated. One of such mechanisms may be associated with the Ni(II)-dependent peptide bond hydrolysis, which occurs before Ser/Thr in Ser/Thr-Xaa-His sequences. Human annexins A1, A2, and A8, proteins modulating the immune system, contain several such s...

The binding of Ni(II) and subsequent metal-dependent hydrolysis of peptide bond occurs in sequences of peptides or proteins of the type Ser/Thr-Xaa-His. His103, His246 and His293 of human annexin A1 are located in the fragments with amino acid sequences Thr-Gly-His, Ser-Lys-His and Thr-Arg-His, respectively, which thus constitute potential nickel b...