Substitution of aspartate and glutamate for active center histidines in the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system maintain phosphotransfer potential.
The active center histidines of the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system proteins; histidine-containing protein, enzyme I, and enzyme IIA(Glc) were substituted with a series of amino acids (serine, threonine, tyrosine, cysteine, aspartate, and glutamate) with the potential to undergo phosphorylation. The mutants [H189E]enzyme I, [H15D]HPr, and [H90E]enzyme IIA(Glc) retained ability for phosphorylation as indicated by [(32)P]phosphoenolpyruvate labeling. As the active center histidines of both enzyme I and enzyme IIA(Glc) undergo phosphorylation of the N(epsilon2) atom, while HPr is phosphorylated at the N(delta1) atom, a pattern of successful substitution of glutamates for N(epsilon2) phosphorylations and aspartates for N(delta1) phosphorylations emerges. Furthermore, phosphotransfer between acyl residues: P-aspartyl to glutamyl and P-glutamyl to aspartyl was demonstrated with these mutant proteins and enzymes.
Napper
S
S
Department of Biochemistry, Health Sciences Building, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5 Canada. Napper@sask.usask.ca
Brokx
S J
SJ
Pally
E
E
Kindrachuk
J
J
Delbaere
L T
LT
Waygood
E B
EB
D001224:Aspartic Acid; D001426:Bacterial Proteins; D004926:Escherichia coli / Q000201:enzymology*; D018698:Glutamic Acid; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; C031629:phosphoenolpyruvate-glucose phosphotransferase