HisB
Encyclopedia
The hisB gene, found in the enterobacteria
(such as E. coli), in Campylobacter jejuni and in Xylella/Xanthomonas encodes a protein involved in catalysis of two step in histidine biosynthesis (the sixth and eight step), namely the bifunctional Imidazoleglycerol-phosphate dehydratase
/histidinol-phosphatase
.
The former function , found at the N-terminal, dehydrated d-erythroimidazoleglycerolphosphate to imidazoleacetolphosphate, the latter function , found at the C-terminal, dephosphorylates l-histidinolphosphate producing histidinol.
The firth step is catalysed instead by histadinolphosphate aminotransferase (encoded by hisC)
The peptide is 40.5kDa and associates to form a hexamer (unless truncated)
In E. coli hisB is found on the hisGDCBHAFI operon
The phosphatase activity possess a substrate ambiguity and overexpression of hisB can rescue phosphoserine phosphatase (serB) knockouts.
hisB-C
from Saccharomyces cerevisiae is not a fused IGP dehydratase and hisidinol phosphatase, but a IGPD only (homologous to hisB-N). Whereas HIS2 is the HP (analogous to hisB-C, called hisJ in some prokaryotes).
Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...
(such as E. coli), in Campylobacter jejuni and in Xylella/Xanthomonas encodes a protein involved in catalysis of two step in histidine biosynthesis (the sixth and eight step), namely the bifunctional Imidazoleglycerol-phosphate dehydratase
Imidazoleglycerol-phosphate dehydratase
In enzymology, an imidazoleglycerol-phosphate dehydratase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, D-erythro-1-glycerol 3-phosphate, and two products, 3--2-oxopropyl phosphate and H2O.This enzyme belongs to the family of lyases, specifically the...
/histidinol-phosphatase
Histidinol-phosphatase
In enzymology, a histidinol-phosphatase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are L-histidinol phosphate and H2O, whereas its two products are L-histidinol and phosphate....
.
The former function , found at the N-terminal, dehydrated d-erythroimidazoleglycerolphosphate to imidazoleacetolphosphate, the latter function , found at the C-terminal, dephosphorylates l-histidinolphosphate producing histidinol.
The firth step is catalysed instead by histadinolphosphate aminotransferase (encoded by hisC)
The peptide is 40.5kDa and associates to form a hexamer (unless truncated)
In E. coli hisB is found on the hisGDCBHAFI operon
The phosphatase activity possess a substrate ambiguity and overexpression of hisB can rescue phosphoserine phosphatase (serB) knockouts.
Reactions
hisB-N- D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate
3-(imidazol-4-yl)-2-oxopropyl phosphate + H2O
hisB-C
- L-histidinol phosphate + H2O
L-histidinol + phosphate
Non-fusion protein in other species
HIS3HIS3
The HIS3 gene, found in the Saccharomyces cerevisiae yeast, encodes a protein called Imidazoleglycerol-phosphate dehydratase which catalyses the sixth step in histidine biosynthesis...
from Saccharomyces cerevisiae is not a fused IGP dehydratase and hisidinol phosphatase, but a IGPD only (homologous to hisB-N). Whereas HIS2 is the HP (analogous to hisB-C, called hisJ in some prokaryotes).