Anion-Binding Properties of Short Linear Homopeptides

Modrušan, Matija; Glazer, Lucija; Otmačić, Lucija; Crnolatac, Ivo; Cindro, Nikola; Vidović, Nikolina; Piantanida, Ivo; Speranza, Giovanna; Horvat, Gordan; Tomišić, Vladislav (2024) Anion-Binding Properties of Short Linear Homopeptides. International Journal of Molecular Sciences, 25 (10). ISSN 1422-0067

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Abstract

A comprehensive thermodynamic and structural study of the complexation affinities of tetra (L1), penta (L2), and hexaphenylalanine (L3) linear peptides towards several inorganic anions in acetonitrile (MeCN) and N,N-dimethylformamide (DMF) was carried out. The influence of the chain length on the complexation thermodynamics and structural changes upon anion binding are particularly addressed here. The complexation processes were characterized by means of spectrofluorimetric, 1H NMR, microcalorimetric, and circular dichroism spectroscopy titrations. The results indicate that all three peptides formed complexes of 1:1 stoichiometry with chloride, bromide, hydrogen sulfate, dihydrogen phosphate (DHP), and nitrate anions in acetonitrile and DMF. In the case of hydrogen sulfate and DHP, anion complexes of higher stoichiometries were observed as well, namely those with 1:2 and 2:1 (peptide:anion) complexes. Anion-induced peptide backbone structural changes were studied by molecular dynamic simulations. The anions interacted with backbone amide protons and one of the N-terminal amine protons through hydrogen bonding. Due to the anion binding, the main chain of the studied peptides changed its conformation from elongated to quasi-cyclic in all 1:1 complexes. The accomplishment of such a conformation is especially important for cyclopeptide synthesis in the head-to-tail macrocyclization step, since it is most suitable for ring closure. In addition, the studied peptides can act as versatile ionophores, facilitating transmembrane anion transport.

Item Type:	Article
Uncontrolled Keywords:	peptides ; chain-length effect ; anion-binding ; thermodynamics ; circular dicroism ; NMR ; spectrofluorimetry ; microcalorimetry ; MD simulations
Subjects:	NATURAL SCIENCES NATURAL SCIENCES > Chemistry NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Organic Chemistry and Biochemistry
Projects:	Project title Project leader Project code Project type Koordinacijske reakcije makrocikličkih liganada u otopini-MacroSol Vladislav Tomišić IP-2019-04-9560 HRZZ Centar izvrsnosti u kemiji - CIuK-CIuK Josip Požar; Mirta Rubčić; Ivana Biljan KK.01.1.1.02.0016 EK
Depositing User:	Ana Zečević
Date Deposited:	22 Jul 2024 09:26
URI:	http://fulir.irb.hr/id/eprint/8957
DOI:	10.3390/ijms25105235

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