Protein-Mimicking Functions of Nano-Size Monoamido Amino Acids Derived from Polysaccharides of Marine Origin

Polysaccharides of marine origin, for example, agarose (Ag) and alginic acid (Alg)-based new nano-size monoamido amino acid derivatives are synthesized and their protein-like characteristics are evaluated. Two new agarose-based nanosize amino acid derivatives are obtained by partial amidation of agarose succinate half-ester (Ag-SA; DS 0.95) employing aliphatic acyclic and cyclic diamines, for example, 1,6-hexamethylenediamine (HDA) and trans-1,4-cyclohexanediamine (CHDA), named Ag-SA-hexamethylene-monoamido (AEAm) and Ag-SA-cyclohexanemonoamido (AECAm) amines (DSs 0.47, 0.35), recording isoelectric points (pIs) 7.9 and 6.4, respectively. Alginic acid, extracted from the Indian seaweed species, Sargassum tenerrimum, is functionalized with ethylene diamine (EDA) affording a nanosize alginic-acid-based monoamido amino acid (Alg-EDA; DS 0.47; pI 3.40). All of these three nanosize monoamido amino acids (DLS; (nm) AEAm 0.65, 80.9; AECAm 0.65, 7.54, and 107.4; Alg-EDA 0.89, 2.0, 50, and 61.0) exhibit protein-mimicking functions interacting with Salman testes DNA and bovine serum albumin (BSA), displaying different complexation and decomplexation profiles in a varying pH regime. These nanobody polysaccharide-based protein-like large molecules may be of potential utility in the domains of pH-responsive drug delivery, separations as well as chiral sensing applications.