Complex coacervates based on recombinant mussel adhesive proteins: their characterization and applications

Complex coacervates are a dense liquid phase of oppositely charged polyions formed by the associative separation of a mixture of polyions. Coacervates have been widely employed in many fields including the pharmaceutical, cosmetic, and food industries due to their intriguing interfacial and bulk material properties. More recently, attempts to develop an effective underwater adhesive have been made using complex coacervates that are based on recombinant mussel adhesive proteins (MAPs) due to the water immiscibility of complex coacervates and the adhesiveness of MAPs. MAP-based complex coacervates contribute to our understanding of the physical nature of complex coacervates and they provide a promising alternative to conventional invasive surgical repairs. Here, this review provides an overview of recombinant MAP-based complex coacervations, with an emphasis on their characterization and the uses of such materials for applications in the fields of biomedicine and tissue engineering.113sciescopu

RECOMBINANT MUSSEL ADHESIVE PROTEIN AS A GENE DELIVERY MATERIAL

Efficient target gene delivery into eukaryotic cells is important for biotechnological research and gene therapy. Gene delivery based on proteins, including histones, has recently emerged as a powerful non-viral DNA transfer technique. Here, we investigated the potential use of a recombinant mussel adhesive protein, hybrid fp-151, as a gene delivery material, in view of its similar basic amino acid composition to histone proteins, and cost-effective and high-level production in Escherichia coli. After confirming DNA binding affinity, we transfected mammalian cells (human 293T and mouse NIH/3T3) with foreign genes using hybrid fp-151 as the gene delivery carrier. Hybrid fp-151 displayed comparable transfection efficiency in both mammalian cell lines, compared to the widely used transfection agent, Lipofectamine (TM) 2000. Our results indicate that this mussel adhesive protein may be used as a potential protein-based gene-transfer mediator.X117sciescopu

Mussel adhesive protein fused with cell adhesion recognition motif triggers integrin-mediated adhesion and signaling for enhanced cell spreading, proliferation, and survival

Abstract: Adhesion of cells to a surface is a basic and important requirement in the fields of cell culture and tissue engineering. Previously, we constructed the cell adhesive, fp-151-RGD, by fusion of the hybrid mussel adhesive protein, fp-151, and GRGDSP peptide, one of the major cell adhesion recognition motifs; fp-151-RGD efficiently immobilized cells on coated culture surfaces with no protein and surface modifications, and apparently enhanced cell adhesion, proliferation, and spreading abilities. In the present study, we investigated the potential use of fp-151-RGD as a biomimetic extracellular matrix material at the molecular level by elucidating its substantial effects on integrin-mediated adhesion and signaling. Apoptosis derived from serum deprivation was significantly suppressed on the fp-151-RGD-coated surface, indicating that RGD-induced activation of integrin-mediated signaling triggers the pathway for cell survival. Analysis of the phosphorylation of focal adhesion kinase clearly demonstrated activation of focal adhesion kinase, a well-established indicator of integrin-mediated signaling, on the fp-151-RGD-coated surface, leading to significantly enhanced cell behaviors, including proliferation, spreading and survival, and consequently, more efficient cell culture

Bulk adhesive strength of recombinant hybrid mussel adhesive protein

Mussel adhesive proteins (MAPs) have received increased attention as potential biomedical and environmental friendly adhesives. However, practical application of MAPs has been severely limited by uneconomical extraction and unsuccessful genetic production. Developing new adhesives requires access to large quantities of material and demonstrations of bulk mechanical properties. Previously, the authors designed fp-151, a fusion protein comprised of six MAP type 1 (fp-1) decapeptide repeats at each MAP type 5 (fp-5) terminus and successfully expressed it in Escherichia coli. This recombinant hybrid protein exhibited high-level expression, a simple purification and high biocompatibility as well as strong adhesive ability on a micro-scale. In the present work, investigations on the bulk adhesive properties of semi-purified (90% purity) fusion fp-151 were performed in air. The unmodified recombinant fp-151, as expressed, contains tyrosine residues and showed significant shear-adhesive forces (0.33MPa). Adhesion strength increased (0.45MPa) after enzymatic oxidation of tyrosine residues to l-3,4-dihydroxyphenylalanine (DOPA) groups. Addition of cross-linkers such as iron(III), manganese(III) and periodate (IO4-) generally enhanced adhesion, although too much addition decreased adhesion. Among the three cross-linking reagents examined, the non-metallic oxidant periodate showed the highest shear-adhesive forces (0.86MPa). In addition, it was found that adhesive strengths could be increased by adding weights to the samples. The highest adhesion strength found was that of DOPA-containing fp-151 cross-linked with periodate and having weights applied to the samples (1.06MPa). Taken together, the first bulk-scale adhesive force measurements are presented for an expressed recombinant hybrid mussel adhesive protein.X113934sciescopu

In vivo post-translational modifications of recombinant mussel adhesive protein in insect cells

Mussel adhesive proteins (MAPs) have been suggested as promising bioadhesives for diverse application fields, including medical uses. Previously, we successfully constructed and produced a new type of functional recombinant MAP, fp-151, in a prokaryotic Escherichia coli expression system. Even though the E. coli-derived MAP showed several excellent features, such as high production yield and efficient purification, in vitro enzymatic modification is required to convert tyrosine residues to l-3,4-dihydroxyphenyl alanine (dopa) molecules for its adhesive ability, due to the intrinsic inability of E. coli to undergo post-translational modification. In this work, we produced a soluble recombinant MAP in insect Sf9 cells, which are widely used as an effective and convenient eukaryotic expression system for eukaryotic foreign proteins. Importantly, we found that insect-derived MAP contained converted dopa residues by in vivo post-translational modification. In addition, insect-derived MAP also had other post-translational modifications including phosphorylation of serine and hydroxylation of proline that originally occurred in some natural MAPs. To our knowledge, this is the first report on in vivo post-translational modifications of MAP containing dopa and other modified amino acid residues. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 1390-1396, 2011X111515sciescopu