Transglutamination allows production and characterization of native-sized ELPylated spider silk proteins from transgenic plants.

In the last two decades it was shown that plants have a great potential for production of specific heterologous proteins. But high cost and inefficient downstream processing are a main technical bottleneck for the broader use of plant-based production technology especially for protein-based products, for technical use as fibres or biodegradable plastics and also for medical applications. High-performance fibres from recombinant spider silks are, therefore, a prominent example. Spiders developed rather different silk materials that are based on proteins. These spider silks show excellent properties in terms of elasticity and toughness. Natural spider silk proteins have a very high molecular weight, and it is precisely this property which is thought to give them their strength. Transgenic plants were generated to produce ELPylated recombinant spider silk derivatives. These fusion proteins were purified by Inverse Transition Cycling (ITC) and enzymatically multimerized with transglutaminase in vitro. Layers produced by casting monomers and multimers were characterized using atomic force microscopy (AFM) and AFM-based nanoindentation. The layered multimers formed by mixing lysine- and glutamine-tagged monomers were associated with the highest elastic penetration modulus.

Comparison of different algorithms for simultaneous estimation of multiple parameters in kinetic metabolic models.

Computational models in systems biology are usually characterized by a lack of reliable parameter values. This is especially true for kinetic metabolic models. Experimental data can be used to estimate these missing parameters. Different optimization techniques have been explored to solve this challenging task but none has proved to be superior to the other. In this paper we review the problem of parameter estimation in kinetic models. We focus on the suitability of four commonly used optimization techniques of parameter estimation in biochemical pathways and make a comparison between those methods. The suitability of each technique is evaluated based on the ability of converging to a solution within a reasonable amount of time. As most local optimization methods fail to arrive at a satisfactory solution we only considered the global optimization techniques. A case study of the upper part of Glycolysis consisting 15 parameters is taken as the benchmark model for evaluating these methods.

Elastin-like polypeptides revolutionize recombinant protein expression and their biomedical application.

Elastin-like polypeptides (ELPs) are highly biocompatible and exhibit a potentially highly useful property: that of a thermally responsive reversible phase transition. These characteristics make ELPs attractive for drug delivery, appealing as materials for tissue repair or engineering, and improve the efficiency with which recombinant proteins can be purified. ELP fusion proteins (referred to as ELPylation) inherit the reversible phase transition property. ELPylation technology recently has been extended to plant cells, and a number of plant-based expression systems have been evaluated for the production of ELPylated proteins. Here, we discuss recent developments in ELP technology and the substantial potential of ELPs for the deployment of transgenic plants as bioreactors to synthesize both biopharmaceuticals and industrial proteins.