Bacterial expression system

One of the best-studied carrier molecules is produced as a primary excretory constituent of the adult male mouse, known from its consistent high concentration as the major urinary protein (MUP). The basic 3-D structure of the protein was initially obtained from a monoclinic crystal of recombinant protein (MUP-I), constructed by induction in a bacterial expression system and purified to homogeneity (Kuser, 1990). A wild type version of MUP finally yielded to NMR analysis a clone of the r-isoform (162 residues) was labelled and compared with the crystal-structure (Lucke et al., 1990). Two views of the molecule... 

Terpe, K. (2006) Overview of bacterial expression systems for heterologous protein production from molecular and biochemical fundamentals to commercial systems. Applied Microbiology and Biotechnology, 72 (2), 211-222. 

The success of Chapman and co-workers in expression of flavocytochrome 2 in E. coli [23] is encouraging in its impUcations for future expression of flavoproteins in this host because, in their experience both the flavin and heme groups are incorporated into the recombinant protein. Moreover, the bacterial expression system produces the protein 500-1000 fold more efficiently than the yeast from which it was cloned. The enzyme produced in E. coli, however, lacks the first five amino acid residues at its amino terminus, a result which presumably reflects subtle differences in protein synthesis between the two organisms. 

With the development of bacterial expression systems for Mb described earlier and with the known diversity of metal coordination... 

Pharmacology Anakinra is a recombinant, nonglycosylated form of the human interleukin-1 receptor antagonist (IL-1 Ra). Anakinra differs from native human IL-IRa in that it has a single methionine residue at its amino terminus. It is produced by recombinant DNA technology using an Escherichia coli bacterial expression system. 

Most target proteins of therapeutic interest are human or mammalian in origin, but some require post-translational modification during expression for optimum biological and pharmacokinetic properties. Bacterial expression systems do not allow most post-translational modifications. In those cases, eukaryotic expression systems are chosen. These systems, however, are more complex and require more time and resources to engineer, especially in mammalian cells. Consequently, the final products produced in mammalian cells are more expensive than those produced by bacterial expression systems. 

C. C. Boesen, S. A. Motyka, A. Patamawenu, and P. D. Sun, Development of a recombinant bacterial expression system for tbe active form of a human transforming growtb factor P type II receptor ligand binding domain, Prot. Expr. Purif. 2000, 20, 98-104. 

Various strategies have been used to combine the variable region of antibodies, which bind to the antigen determinants, with small functional proteins. Such constructs can be produced on a large scale in various expression systems (Irving et al., 1996 Roque et al., 2004) bacterial expression systems are relatively simple and less expensive than the alternatives, but eukaryote expression systems (yeast, mammalian, and insect cells) are also being used for this purpose (Roque et al., 2004). 

In conclusion, it should be pointed out that in marked contrast to the very extensive studies on rabbit muscle phosphorylase, little attention has been paid to enzymes from other sources. However, primary structures of plant phosphorylases have now been determined and bacterial expression systems for the plant enzymes have also been made available as reviewed in this article. We hope that future studies on the structure and function of plant phosphorylases without allosteric regulation and comparison with those of the highly regulated animal enzyme will provide valuable information on this interesting group of enzymes, phosphorylases. 

What characteristics of glutathione-S-trans-ferase make it an attractive affinity tag for use in bacterial expression systems ... 

The immediate product of the oxidative reaction, the monodehydroascorbate radical (Eq. [1]), is a fairly reactive and unstable species which, in the presence of a suitable reductase system, is reduced back to ascorbate. Monodehydroascorbate reductases have been identified and purified in a few cases (Ushimara et al., 1997 Dalton et al., 1992 Shigeoka et al., 1987 Borraccino et al., 1986 Hossain et al., 1984) and cDNA sequences have been published for the pea (Murthy and Zilinskas, 1994) and cucumber enzymes (Sano et al., 1995). A bacterial expression system is also available for the cucumber enzyme (Sano et al., 1995). In the absence of a suitably efficient reductase system, the monodehydroascorbate radicals disproportionate to dehydroascorbate and ascorbate in this case, ascorbate is regenerated using a glutathione-dependent dehydroascorbate reductase enzyme (Foyer and Mullineaux, 1998 and references therein). Under non-... 

Hence, we conclude that the higher molecular weight form of NT-3 was caused by reading through of the UGA stop codon by tryptophan incorporation. The UGA codon has been well documented to be leaky in early study on microbial molecular biology (9). Its use should be minimized in bacterial expression system. 

Immunological techniques. The source of andgen could be overpro-ducdon by a bacterial expression system or purified nadve andgen. 

The volumetric productivity achievable in simple bioreactor systems when using bacterial expression systems is superior to that of mammalian expression systems. Growth rates are higher, and the ease of scale-up of the fermentation process enables manufacturing at scales up to five-fold larger compared to mammalian systems. 

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