Mutants around

E. coli have also been determined (3, 9, 24-26). Figure 1 depicts the polypeptide backbone of the yeast enzyme, indicating the position of the heme, and the proximal and distal histidine residues. The structure can be divided into N- and C-terminal domains, and the heme is in a cavity at the domain interface. The substrate access channel is also at the domain interface and is discussed in Section V. The secondary structure is dominated by a-helices with only a small amount of jS-sheet in the proximal domain. The refined structures of the recombinant wild-type enzymes are essentially identical to that of the yeast enzyme, but small differences are observed in the mutants around the mutated residues (3). 

In another study that appeared prior to the advent of CASTing, the traditional combination of epPCR and DNA shuffling was used to enhance the enantioselectivity of the hydrolytic kinetic resolution of p-nitro phenyl glycidyl ether and other epoxides catalyzed by the EH from Agrobacterium radiobacter [59]. Several mutants were obtained with up to 13-fold improved enantioselectivity. The amino acid exchanges took place around the active site. 

For example, Fig. 9.40 shows the NIS spectra of the oxidized and reduced FeS4 centers of a rubredoxin mutant from Pyrococcus abyssi obtained at 25 K together with DFT simulations using different models for the Fe-S center [103]. The spectrum from the oxidized protein Fe S4 (S = 5/2) reveals broad bands around 15-25 meV (121-202 cm ) and 42-48 meV (339-387 cm ) consistent with the results on rubredoxin from Pyrococcus furiosus [104]. 

Gcincgy Yes. Because AP polarity appears normal in gyg-8 mutant embryos, we expected that gyg-8 mutant embryos would be able to respond to changes in AP polarity. In other words, if a %yg-8 mutant embryo is also lacking par-2 or par-3 function, the spindle should no longer shoot to the posterior, but instead go to random locations around the circumference of the embryo. This is exactly what we observed, at least to a first approximation. 

Wild-type and mutant enzymes Main a-linkage in glucan products Amino acid sequence around transition-state stabilizer D627 in GTFR... 

The above model was used to study the binding of methotrexate, and analogues of it, to wild-type and mutant forms of human dihydrofolate reductase (DHFR).29 This turned out to be a particularly difficult test because of the three ionized groups of methotrexate. The overall electrostatic interactions of this inhibitor amount to around -500 kcal/mol and MD trajectories of length more than a ns were required in order to get average... 

Neuropathies can result from mutations that alter the structure or level of expression of PNS myelin proteins (e.g. overexpression of PMP22 in Charcot-Marie-Tooth syndrome (CMT) type 1A), the metabolism of myelin lipids (e.g. metachromatic leukodystrophy), or the capacity of PNS neurons to support their axons in patients with CMT caused by mutations of KIF1B [4] or NF-L [5, 6]. Both acquired and inherited amyloid neuropathies can result from the deposition of poorly soluble proteins, for example cryoglobulins or mutant transthyretins, in and around endoneurial bloodvessels [7-9]. 

Sanders The WWvs are natural mutants. They have been around for a long time. 

Interestingly, we have recently identified a mutation of a tyrosine in the third intracellular loop of the hDAT that causes a major alteration in the conformational equilibrium of the transport cycle, and thus as such is comparable to mutants on G protein-coupled receptors causing constitutive isomerization of the receptor to the active state (66). Most importantly, this conclusion is based on the observation that mutation of the tyrosine completely reverts the effect of Zn2+ at the endogenous Zn2+ binding site in the hDAT (50,51) from potent inhibition of transport to potent stimulation of transport (Fig. 6). In the absence of Zn2+, transport capacity is reduced to less than 1% of that observed for the wild-type, however, the presence of Zn2+ in only micromolar concentrations causes a close to 30-fold increase in uptake (66). Moreover, it is found that the apparent affinities for cocaine and several other inhibitors are substantially decreased, whereas the apparent affinities for substrates are markedly increased (66). Notably, the decrease in apparent cocaine affinity was around 150-fold and thus to date the most dramatic alteration in cocaine affinity reported upon mutation of a single residue in the monoamine transporters (66). 

This enzyme from E. coli is a tetramer of four identical subunits, each of molecular weight 116,500. Amber and ochre (premature termination) mutants of the enzyme provide a number of enzymically inactive, incomplete peptide chains, identical in sequence with the N-term nal part of the wild-type chains. A subset of these N-terminal peptides, called acceptor peptides, can combine with so-called wild-type chain, to restore enzymic activity (Ullmann et al., 1965, 1967 Ullmann and Perrin, 1970 see also the review by Zabin and Villarejo, 1975). Goldberg (1969) suggested that the acceptor peptides and the independent nucleation centers as evidenced by the following facts ... 

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