Cyclohydrolase

Function

• GTP cyclohydrolase I catalyzes the conversion of GTP to 7,8-dihydronepterin triphosphate. GCH I is part of the folate and biopterin biosynthesis
• GTP cyclohydrolase II catalyzes the conversion of GTP to formate, diphosphate and diamino-hydroxy-phosphoribosylamino pyrimidine. GCH II is part of riboflavin metabolism.
• IMP cyclohydrolase catalyzes the conversion of IMP to formido-phosphosibosyl imidazole carboxamide. ICH is part of the purine biosynthesis
• Methenyltetrahydromethanopterin cyclohydrolase catalyzes the conversion of methenyltetrahydromethanopterin to formyl-tetrahydromethanopterin. MCH is part of the folate biosynthesis

Disease

Relevance

Structural highlights

3D structures of cyclohydrolase

Updated on 17-July-2014

GTP cyclohydrolase I

1gtp – EcGCH I – Escherichia coli
3d1t – NgGCH IB + Zn – Neisseria gonorrhoeae
3d2o – NgGCH IB + Mn
1fb1 – hGCH I + Zn – human
1wm9 – TtGCH I + Zn – Thermus thermophilus

GTP cyclohydrolase I complexes

1a8r, 1a9c, 1n3r, 1n3t, 1n3s – EcGCH I (mutant) + GTP

4du6 – GCH I + GTP – Yersinia pseudotuberculosis
1fbx – EcGCH I + Zn
1wuq, 1wur – TtGCH I + Zn + 8-oxo-GTP
1is7 – rGCH I + GCH feedback regulatory protein - rat
1is8 – rGCH I + GCH feedback regulatory protein + Zn
1wpl – rGCH I + GCH feedback regulatory protein + Zn + dihydrobiopterin

GTP cyclohydrolase II

2bz1 – EcGCH II + Zn
2bz0 – EcGCH II + Zn + phosphomethylphosphonic acid guanylate

GTP cyclohydrolase III

2qv6 – GCH III + GTP + Ca – Methanocaldococcus jannaschii

IMP cyclohydrolase

2ntm – MtICH – Methanothermobacter thermoautotrophicus
2ntk – MtICH + IMP
2ntl – MtICH + AICAR

Methenyltetrahydromethanopterin cyclohydrolase

1qlm – MCH – Methanopyrus kandleri
4gvr – AfMCH – Archaeoglobus fulgidus
4gvq – AfMCH + tetrahydromethanopterin
4gvs – AfMCH + N5-formyl-tetrahydromethanopterin

Phosphoribosyl-ATP cyclohydrolase

1zps – MtPCH + Cd

References