Mutants system

Table 4. Results of fed-batch cultures of pMW618/ arL mutant system ...

Russa, R., Urbanik-Sypniewska, T., Shashkov, A.S., Banaszek, A., Zamojski, A., Mayer, H. Partial structure of lipopolysaccharide isolated from Rhizobium leguminosarum bv. trifolii 24 and its GalA-negative Exo" mutant. System Appl Microbiol 19 (1996) 1-8. 

Finnish hereditary amyloidosis Fragments of gelsolin mutants Systemic... 

In early examinations of the shUdmate pathway leading to aromatic compounds, a number of possible precursor compounds were evaluated. Surprisingly, out of about 50 compounds tested in mutant systems, only shikimic acid was found to be utilized. This compound could replace all three common aromatic amino acids and />-aminobenzoic acid (Weiss and Edwards, 1981). 

Mann, G., Prins, J., Hermans, J. Energetics of forced extraction of ligand Simulation studies of Xe in mutant T4 lysozyme as a simple test system. Bioohys. J., in preparation (1998)... 

The critical factor for any method involving an approximation or an extrapolation is its range of application. Liu et al. [15] demonstrated that the approach performed well for mutations involving the creation or deletion of single atoms. The method has also been successfully applied to the prediction of the relative binding affinities of benzene, toluene and o-, p-, and m-xylene to a mutant of T4-lysozyme [16]. In both cases, however, the perturbation to the system was small. To investigate range over which the extrapolation may... 

These results indicate that is it possible to change the fold of a protein by changing a restricted set of residues. They also confirm the validity of the rules for stability of helical folds that have been obtained by analysis of experimentally determined protein structures. One obvious impliction of this work is that it might be possible, by just changing a few residues in Janus, to design a mutant that flip-flops between a helical and p sheet structures. Such a polypeptide would be a very interesting model system for prions and other amyloid proteins. 

Furthermore, if the antibiotic passes membranes through a specific port of entry, its mutational loss leads to resistance. The lack of the outer membrane protein OprD in P. aeruginosa causes resistance to the (3-lactam antibiotic imipenem. Fosfomycin passes the cytoplasmic membrane via an L-a-glycerol phosphate permease. This transport system is not essential for bacterial growth and therefore mutants with a reduced expression are frequently selected under therapy. 

Disorders caused by misfolded mutant proteins that fail to pass the quality control system of the ER (e.g., mutations of the cystic fibrosis transmembrane regulator protein (CFTR) causing cystic fibrosis). The mutant proteins are retrotranslocated into the cytosol and finally subjected to proteolysis. In some... 

Neither chemical nor pharmacological chaperones lead to wild-type expression levels of the mutant proteins at the cell surface. Alternative or additional strategies are needed to improve the intracellular transport of the mutant proteins. In the future, dtugs may also be developed that influence those components of the quality control system that are involed in the retention of misfolded proteins. 

The organism utilized is a mutant of E. coli blocked in the synthesis of aromatic amino acids before the shikimate step. Cells are first grown in the presence of adenosine, a technique that temporarily derepresses the system of en-... 

---