Cu(II) coordination to His-containing linear peptides and related branched ones: Equalities and diversities.

Cu(II) coordination to His-containing linear peptides and related branched ones: Equalities and diversities.
J Inorg Biochem. 2020 Jan 03;205:110980
Authors: Perinelli M, Guerrini R, Albanese V, Marchetti N, Bellotti D, Gentili S, Tegoni M, Remelli M
Abstract
The two branched peptides (AAHAWG)4-PWT2 and (HAWG)4-PWT2 where synthesized by mounting linear peptides on a cyclam-based scaffold (PWT2), provided with four maleimide chains, through a thio-Michael reaction. The purpose of this study was primarily to verify if the two branched ligands had a Cu(II) coordination behavior reproducing that of the single-chain peptides, namely AAHAWG-NH2, which bears an Amino Terminal Cu(II)- and Ni(II)-Binding (ATCUN) Motif, and HAWG-NH2, which presents a His residue as the N-terminal amino acid, in a wide pH range. The study of Cu(II) binding was performed by potentiometric, spectroscopic (UV-vis absorption, CD, fluorescence) and ESI-MS techniques. ATCUN-type ligands ((AAHAWG)4-PWT2 and AAHAWG-NH2) were confirmed to bind one Cu(II) per peptide fragment at both pH 7.4 and pH 9.0, with a [NH2, 2N-, NIm] coordination mode. On the other hand, the ligand HAWG-NH2 forms a [CuL2]2+ species at neutral pH, while, at pH 9, the formation of 1:2 Cu(II):ligand adducts is prevented by amidic nitrogen deprotonation and coordination, to give rise solely to 1:1 species. Conversely, Cu(II) binding to (HAWG)4-PWT2 resulted in the formation of 1:2 copper:peptide c...

Source: Journal of Inorganic Biochemistry - January 2, 2020 Category: Biochemistry Authors: Perinelli M, Guerrini R, Albanese V, Marchetti N, Bellotti D, Gentili S, Tegoni M, Remelli M Tags: J Inorg Biochem Source Type: research