The Benefits of Cell-Free Systems

Such excellent outcomes are a result of careful and systematic optimization of DNA constructs and expression conditions. There are occasions, however, where proteins fail to express, or are expressed in an inactive form. Other proteins express well in one expression system, but not in another, and this is of course also trae of aU in vivo expression systems. A true benefit of cell-free synthesis over in vivo methods is that the open nature of the systems presents the researcher with unparalleled opportunities to affect the outcome of an expression experiment. As such, cell-free synthesis methods represent an invaluable addition to any laboratory investigating the expression of biopharmaceuticals. 

In the broadest terms, cell-free synthesis offers advantages over traditional in vivo methods of recombinant protein expression, as it enables the experimentalist strictly to control conditions under which expression reactions are performed. Benefits of such an open expression system are exemplified by the fact that cell-free reaction conditions can be sufficiently modified to support co-translational folding of active disulfide-bonded proteins. 

The PURE system is important as it def initively established the minimum requirements for high-level expression in an E. coli cell-free system. The benefits of this system include the elimination of pro-... 

Beyond understanding pathway operation in a cell-like extract environment, crude lysate systems have also been exploited to create other building blocks. For example, the synthesis of triketone precursors, essential for some antibiotics, have been pursued in cell-free systems [73], In E. coli crude lysates, enzymes from Bacillus subtilis were overexpressed to achieve triketide lactone production. While the scientists briefly use this system to characterize enzymes in the pathway, this is a good example of how different properties such as chirality can be achieved through manipulation of enzyme activities. However, this system does not take advantage of any of the benefits of crude lysate and therefore could be performed in a purified system as well. This still remains an important finding in the growing body of CFME literature. 

In recent years the concept of a fuel cell propulsion system has gained in attention as a result of the need to reduce the fossil fuel consumption and greenhouse gas emissions. Since the fuel cells suitable for vehicle application (polymeric electrolyte membrane fuel cells) are fuelled by hydrogen, and deliver power as long as fuel and air are supplied, they potentially can provide the range capabilities of an internal combustion engine when used in a power system, but with clean and quiet operation. Therefore, the fundamental benefit of this type of propulsion consists in the possibility to adopt pollution-free electric drive-trains, without the drive range limitations typical of traditional electric vehicles. 

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