Dissecting the Polyhydroxyalkanoate-Binding Domain of the PhaF Phasin: Rational Design of a Minimized Affinity Tag

Abstract

Polyhydroxyalkanoates (PHAs) are biocompatible, nontoxic, and biodegradable biopolymers with exceptional applications in the industrial and medical fields. The complex structure of the PHA granule can be exploited as a toolbox to display molecules of interest on their surface. Phasins, the most abundant group of proteins on the granule, have been employed as anchoring tags to obtain functionalized PHA beads for high-affinity bioseparation, enzyme immobilization, diagnostics, or cell targeting. Here, a shorter module based on the previously designed BioF tag has been demonstrated to maintain the affinity for the PHA granule, with higher stability and similar functionalization efficiency. The use of a 67% shorter peptide, which maintains the binding properties of the entire protein, constitutes an advantage for the immobilization of recombinant proteins on the PHA surface both in vitro and in vivo .