Myoglobin-directed assemblies of binary monolayers functionalized with iminodiacetic acidligands at the air–water interface through metal coordination for multivalent protein binding

Abstract

Myoglobin binding to the binary monolayers composed of sodium hexadecylimino diacetate and hexadecanol at the air–water interface by means of metal coordination has been investigated using infrared reflection absorption spectroscopy (IRRAS). In the absence of Cu²⁺, no myoglobin binding to the binary monolayers was observed. In the presence of Cu²⁺, remarkable myoglobin binding to the binary monolayers resulted from the formation of ternary complexes of iminodiacetate (IDA)–Cu²⁺–surface histidine. Myoglobin-directed assemblies of the binary monolayers facilitated multivalent protein binding through lateral rearrangements of the IDA ligands and reorientations of the alkyl chains for enhanced protein binding. Myoglobin binding to and desorption from the binary monolayers could be readily controlled through metal coordination.