Fe(III)/Polydopamine-Mediated Capture and Release of Catecholic Compounds

摘要

The special properties of some marine organisms such as underwater adhesive property of mussel1 and silica-forming ability of diatom2 are related to proteins comprising non-natural amino acids, and hence, various efforts have been made to isolate and identify these proteins.Boronate affinity chromatography (BAC) is a representative method to isolate proteins containing unnatural amino acid, 3,4-dihydroxyphenyl-L-alanine (DOPA). In BAC, catechol-containing molecules are selectively bound to the resin modified with phenylboronic acids, resulting in the purification of the molecules.5 Because of the presence of the catechol unit in DOPA, BAC has been frequently employed to purify DOPA-containing proteins. For example, BAC was used in the analysis of squid beak which is known as one of the hardest organic materials. Ali et al. performed various chemical analyses including BAC, and found that the squid beak consists of chitin, water, and DOPA-containing proteins. Although the exact role of DOPA-containing proteins has not been elucidated, the identification of the specific protein provided a meaningful insight to understand the extraordinary mechanical properties of squid beak. BAC has been also utilized in the analysis of sandcastle worm's underwater adhesion.4 Sandcastle worm is well-known that it utilizes the protein-based, underwater adhesive for the construction of its home. Zhao etal. identified the cysteinyl-dopa residues from the adhesive and proposed that the ad-hesive is hardened by crosslinking reaction between DOPA and cysteine groups in proteins. In the study, BAC also played a crucial role for identifying cysteinyl-dopa residues.