Information on EC 4.3.1.B2 - imidazole glycerol phosphate synthase and Organism(s) Escherichia coli and UniProt Accession P60664

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IGP synthase

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L-glutamine + H2O = L-glutamate + NH3

(1a)

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + L-glutamine = L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

overall reaction

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3 = D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

(1b)

L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

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N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + L-glutamine

L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

for the IGP synthase holoenzyme L-glutamine is a more efficient substrate relative to ammonium ion by a factor of 1000. The HisF subunit alone does not ulilize L-glutamine. It supports an ammonia-dependent reaction with a turnover number similar to that of the holoenzyme with glutamine

D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR

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N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH3

D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

the protein encoded by the hisF gene has an ammonia-dependent activity, it does not utilize L-glutamine as substrate. The ammonia-dependent reaction is completely independent of the HisH protein

D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR

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N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + NH4+

D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

the protein encoded by the hisF gene has an ammonia-dependent activity, it does not utilize L-glutamine as substrate. The ammonia-dependent reaction is completely independent of the HisH protein

D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR

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NH4+ + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

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additional information

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2 entries

L-glutamine + N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

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?

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate + L-glutamine

L-glutamate + D-erythro-1-(imidazol-4-yl)glycerol phosphate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

for the IGP synthase holoenzyme L-glutamine is a more efficient substrate relative to ammonium ion by a factor of 1000. The HisF subunit alone does not ulilize L-glutamine. It supports an ammonia-dependent reaction with a turnover number similar to that of the holoenzyme with glutamine

D-erythro-1-(imidazol-4-yl)glycerol phosphate i.e. (2R,3S)-2,3-dihydroxy-3-(1H-imidazol-4-yl)propyl phosphate. 5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide i.e. [(2R,3S,4R,5R)-5-(4-carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphate i.e. AICAR

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MgCl2

10 mM, activity is reduced by 22%

MnCl2

10 mM, activity is reduced by 58%

0.0015 - 5.4

L-glutamine

3 entries

0.0125 - 0.24

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

15 - 16

NH3

2 entries

1 - 291

NH4+

additional information

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kinetic model

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0.13 - 8.5

L-glutamine

3 entries

3.7 - 9.1

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

8.6

NH3

pH 8.0, 30°C, HisF subunit

4.3 - 8.8

NH4+

additional information

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kinetic model

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0.013 - 5700

L-glutamine

3 entries

38 - 300

N1-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamido-1-beta-D-ribofuranosyl 5'-phosphate

0.55 - 0.57

NH3

2 entries

0.03 - 0.581

NH4+

additional information

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kinetic model

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6 - 8

L-glutamine-dependent activity catalyzed by IGP synthase holoenzyme

8

assay at

8 - 9

ammonia-dependent activity catalyzed by HisF

8.5

85% of maximal activity, L-glutamine-dependent activity catalyzed by IGP synthase holoenzyme

9.5

22% of maximal activity, L-glutamine-dependent activity catalyzed by IGP synthase holoenzyme

30

assay at

11600

1 * 11600 (HisH) + 1 * 31600 (HisF), gel filtration (Sephacryl S-100), the HisH and HisF proteins form a stable 1:1 dimeric complex that constitutes the imidazole glycerol phosphate synthase holoenzyme

21655

1 * 21655 (HisH) + 1 * 28457 (HisF), calculated from sequence, the HisH and HisF proteins form a stable 1:1 dimeric complex that constitutes the imidazole glycerol phosphate synthase holoenzyme

28457

1 * 21655 (HisH) + 1 * 28457 (HisF), calculated from sequence, the HisH and HisF proteins form a stable 1:1 dimeric complex that constitutes the imidazole glycerol phosphate synthase holoenzyme

31600

1 * 11600 (HisH) + 1 * 31600 (HisF), gel filtration (Sephacryl S-100), the HisH and HisF proteins form a stable 1:1 dimeric complex that constitutes the imidazole glycerol phosphate synthase holoenzyme

47500

gel filtration

dimer

heterodimer

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C124R

IGP synthases formed with Q123R mutant HisF subunit has no measurable activity with glutamine in vitro

E46G

IGP synthases formed with E46G mutant HisF subunit shows 2800fold reduction in the kcat/Km ratio for glutamine

Q123R

IGP synthases formed with Q123R mutant HisF subunit has no measurable activity with glutamine in vitro

R5H

IGP synthases formed with R5H mutant HisF subunit shows 1500fold reduction in the kcat/Km ratio for glutamine

27

30 d, imidazole glycerol phosphate synthase holoenzyme, 50% loss of activity. The HisF and HisH proteins exhibit half-lives of less than 48 h under similar conditions

27°C, 30 days, imidazole glycerol phosphate synthase holoenzyme, 50% loss of activity

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Klem, T.J.; Davisson, V.J.

Imidazole glycerol phosphate synthase: the glutamine amidotransferase in histidine biosynthesis

Biochemistry

32

5177-5186

1993

Escherichia coli (P60595 and P60664), Escherichia coli

8494895

Demin, O.V.; Goryanin, I.I.; Dronov, S.; Lebedeva, G.V.

Kinetic model of imidazologlycerol-phosphate synthetase from Escherichia coli

Biochemistry

69

1324-1335

2004

Escherichia coli

15627387