Wilds modification of the

Synthesis with addition of 1 G-atom—Wilds modification of the Arndt-Eistert synthesis s. 17, 858... 

In contrast to the large variety of aromatic, olefinic, and aliphatic aldehydes which can be used as donor substrates, wild-type BFD does not tolerate a modification of the methyl group of acetaldehyde in the case of aliphatic acceptor aldehydes. Apart from acetaldehyde, BFD shows activity with aromatic and heteroaromatic aldehydes as the acceptor substrate, forming enantiomerically pure (R)-benzoin and derivatives (Table 2.2.7.3, entries 6-8) [55]. 

The new aldolase differs from all other existing ones with respect to the location of its active site in relation to its secondary structure and still displays enantiofacial discrimination during aldol addition. Modification of substrate specificity is achieved by altering the position of the active site lysine from one /3-strand to a neighboring strand rather than by modification of the substrate recognition site. Determination of the 3D crystal structure of the wild type and the double mutant demonstrated how catalytic competency is maintained despite spatial reorganization of the active site with respect to substrate. It is possible to perturb the active site residues themselves as well as surrounding loops to alter specificity. 

The fiber Because the fiber seems to be primarily responsible for binding of wild-type adenoviruses to cells, most studies focus on modification of the fiber. This work is summarized below. 

A monoclonal antibody which reacts with an epitope within the M domain has recently been used to check whether it influences the receptor s DNA binding properties [65]. The immune complex with wild-type receptors was indeed found to chromatograph on DNA-cellulose similar to nt1 mutant receptors or the chymo-trypsin-degraded wild-type. Reaction with the antibody mimics the removal of the M domain which suggests that biochemical modifications of the M domain could... 

One can notice that while a shift is observed only for two mutants, the fractional intensities obtained from the lifetime measiu cments are modified in the wild type and in the three mutants (Table 2.7). Emission peak of Tryptophan 4 is not modified with the state of ligation, however fractional intensities ft and increase while f3 is not modified. Emission of tryptophan 170 is located at 338 nm characterizing an emission from a slightly hydrophobic environment. Modification of the state of ligation, Mg instead of Ca, and in the apo form, a red shift to 341 and 350 nm is observed. This means that conformational changes are observed in the vicinity of Trp 170 that is more exposed to the solvent in presence of Mg than in presence of Ca. In the apo form, important structural modifications occur within the protein. 

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