Recombinant protein-based polymers

Future Trends for Recombinant Protein-Based Polymers The Case Study of Development and Application of Silk-Elastin-Like... 

Production of Recombinant Protein-Based Polymers (rPBPs)... 

Future Trends for Recombinant Protein-Based Polymers 313... 

Recombinant protein-based polymers are rarely reported as being optically transparent, however, SELP-47K thin films are optically transparent to visible light with notable transmittance in the wavelength range of 350-800 mn [65,66]. Increasing the thickness (from 16 to 92 p,m) had a slight effect in the transmittance with a reduction of about 3% [65]. This optical transparency is maintained even after methanol-induced crystallization, with only a slight reduction in the transmittance from 95 to 92% at 800 nm. 

Precise control of the sequence of amino acid residues Any protein-based polymer sequence utilizing the 20 naturally occurring monomers can be specified using recombinant DNA technology. This allows for equivalent ease of production of diverse protein-based polymer sequences, many of which would otherwise be quite difficult or essentially impossible to prepare due to problems of chemical synthesis and unfavorable energetics in the final polymer. 

Protein-based polymers have the potential to surpass the polyesters and other polymers because they can be directly produced in microorganisms and plants by recombinant DNA technology resulting in the capacity for diverse and precisely controlled composition and sequence. This is not possible with any other polymer, and it increases range of properties and the numbers of applications. Remarkably, with the proper design of composition, protein-based materials can be thermoplastics, melting at temperatures as much as 100°C below their decomposition temperatures. Therefore, they can be molded, extruded, or drawn into shapes as desired. Aspects of protein-based materials as plastics is also considered below. 

A flow diagram for construction of genes for the production of protein-based polymers is given in Figure 9.1. Interestingly, no new or specialized techniques were required for the use of recombinant DNA technology in the... 

Figure 9.1. Diagram showing the approach whereby recombinant DNA technology was used to construct monomer and multi-mer genes for expression of the elastic protein-based polymer [(GVGVP)io]n(GVGVP). (Reproduced with permission from Woods. )...

The advent of recombinant DNA technology, two decades after the remarkable Merrifield advance, has overtaken many of the advantages of the Merrifield approach. After the time-consuming gene construction and development of a good expression system, large quantities of elastic protein-based polymers are produced in a short time, as shown in Figure 9.5. 

Machado R, Ribeiro AJ, Padrao J, Silva D, Nobre A, Teixerra JA, Arias FJ, Cunha AM, Rodriguez-Cabello JC, Casal M (2009) Exploiting the sequence of naturally occurring elastin construction, production and characterization of a recombinant thermoplastic protein based polymer. J Nano Res 6 133—145... 

In this volume not all stress types are treated. Various aspects have been reviewed recently by various authors e.g. The effects of oxygen on recombinant protein expression by Konz et al. [2]. The Mechanisms by which bacterial cells respond to pH was considered in a Symposium in 1999 [3] and solvent effects were reviewed by de Bont in the article Solvent-tolerant bacteria in biocatalysis [4]. Therefore, these aspects are not considered in this volume. Influence of fluid dynamical stresses on micro-organism, animal and plant cells are in center of interest in this volume. In chapter 2, H.-J. Henzler discusses the quantitative evaluation of fluid dynamical stresses in various type of reactors with different methods based on investigations performed on laboratory an pilot plant scales. S. S. Yim and A. Shamlou give a general review on the effects of fluid dynamical and mechanical stresses on micro-organisms and bio-polymers in chapter 3. G. Ketzmer describes the effects of shear stress on adherent cells in chapter 4. Finally, in chapter 5, P. Kieran considers the influence of stress on plant cells. 

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