The only histidine residue in the H31N-H137N double mutant of phage lambda lysozyme (lambdaL), at position 48, was biosynthetically replaced by the analogue 1,2,4-triazole-3-alanine (Taz), the basicity of which is 3 pKa units lower. A histidine-auxotrophic strain was grown to
The effect of the substitution of the active site histidine 48 by the unnatural 1,2,4-triazole-3-alanine (TAA) amino acid analogue in porcine pancreas phospholipase A2 (PLA2) was studied. TAA was introduced biosynthetically using a his-auxotrophic Escherichia coli strain. To study solely
A simple synthetic approach to racemic N-tert-butyloxycarbonyl-2-methyl-3-(1H-1,2,4-triazol-1-yl)alanine (5) in four steps and 68% overall yield starting from oxazoline derivative 1 is reported. This synthesis involves the alkylation of 1H-1,2,4-triazole with an O-tosyloxazoline derivative, followed by an oxazoline ring-opening reaction and
Proteins containing unnatural amino acids have immense potential in biotechnology and medicine. We prepared several histidine analogues including a novel histidine analogue, beta-(1,2,3-triazol-4-yl)-DL-alanine. These histidine analogues were assayed for translational activity in histidine-auxotrophic Escherichia coli strain UTH780. We observed that
The standard Salmonella tester strains used to detect base substitution mutations carry the hisG428 ochre mutation (TA102 and TA104) and the hisG46 missense mutation (TA100). These mutations can be reverted by base changes at their mutant his loci or at
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