Journal of Bacteriology · 1992 · 111 citations · 57 references
Life SciencesBiochemistryMolecular BiologyEnzymologyGene ExpressionGenetic EngineeringCodon EvolutionEnzyme ExpressionEnzyme ProductionMicrobial Enzyme ProductionPlasmid GeneticsProtein Expression EngineeringAmino AcidsDihydropteroate Synthase MutationEnzyme Expression In BacteriaEscherichia ColiEscherichia Coli Expression SystemsPoint Mutation AnalysisPoint Mutation EffectsTemperature-sensitive Mutants
The Escherichia coli gene coding for dihydropteroate synthase (DHPS) has been cloned and sequenced. The protein has 282 amino acids and a compositional molecular mass of 30,314 daltons. Increased expression of the enzyme was realized by using a T7 expression system. The enzyme was purified and crystallized. A temperature-sensitive mutant was isolated and found to express a DHPS with a lower specific activity and lower affinities for para-aminobenzoic acid and sulfathiazole. The allele had a point mutation that changed a phenylalanine codon to a leucine codon, and the mutation was in a codon that is conserved among published DHPS sequences.
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