Literature summary for 3.5.4.27 extracted from

Upadhyay, V.; Demmer, U.; Warkentin, E.; Moll, J.; Shima, S.; Ermler, U.
Structure and catalytic mechanism of N5,N10-methenyl-tetrahydromethanopterin cyclohydrolase (2012), Biochemistry, 51, 8435-8443.

Search for more literature for 3.5.4.27

Cloned(Commentary)

Cloned (Comment)	Organism
overexpression in Escherichia coli	Archaeoglobus fulgidus

Crystallization (Commentary)

Crystallization (Comment)	Organism
hanging drop vapor diffusion method in an anaerobic tent with an atmosphere of 95% N2/5% H2 under low-intensity red light. X-ray structures of the substrate-free E186Q mutant enzyme, the enzyme:5,10-methenyl-5,6,7,8-tetrahydromethanopterin complex, and the E186Q mutant enzyme:5-formyl-5,6,7,8-tetrahydromethanopterin complex	Archaeoglobus fulgidus

Protein Variants

Protein Variants	Comment	Organism
E186A	Vmax is 0.035% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 2.1fold lower compared to wild-type value	Archaeoglobus fulgidus
E186D	Vmax is 0.56% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.1fold higher compared to wild-type value	Archaeoglobus fulgidus
E186N	Vmax is 0.1% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.1fold lower compared to wild-type value	Archaeoglobus fulgidus
E186Q	nearly inactive mutant enhzyme	Archaeoglobus fulgidus
F190V	no activity	Archaeoglobus fulgidus
K94E	Vmax is 86% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.4fold lower compared to wild-type value	Archaeoglobus fulgidus
K94V	Vmax is 41% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.2fold lower compared to wild-type value	Archaeoglobus fulgidus
R183a	Vmax is 0.07% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.3fold lower compared to wild-type value	Archaeoglobus fulgidus
R183E	Vmax is 0.01% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 2.2fold lower compared to wild-type value	Archaeoglobus fulgidus
R183E/E186Q	no activity	Archaeoglobus fulgidus
R183K	Vmax is 15% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.3fold lower compared to wild-type value	Archaeoglobus fulgidus
R183Q	Vmax is 0.05% of wild-type activity, Km for 5,10-methenyl-5,6,7,8-tetrahydromethanopterin is 1.3fold lower compared to wild-type value	Archaeoglobus fulgidus

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.025	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme R183E	Archaeoglobus fulgidus
0.026	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme E186A	Archaeoglobus fulgidus
0.043	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme R183A	Archaeoglobus fulgidus
0.043	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme R183K	Archaeoglobus fulgidus
0.043	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme R183Q	Archaeoglobus fulgidus
0.047	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme K94V	Archaeoglobus fulgidus
0.05	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme E186N	Archaeoglobus fulgidus
0.055	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, wild-type enzyme	Archaeoglobus fulgidus
0.062	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme E186D	Archaeoglobus fulgidus
0.077	-	5,10-methenyl-5,6,7,8-tetrahydromethanopterin	pH 7.6, 65°C, mutant enzyme K94E	Archaeoglobus fulgidus

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
5,10-methenyl-5,6,7,8-tetrahydromethanopterin + H2O	Archaeoglobus fulgidus	-	5-formyl-5,6,7,8-tetrahydromethanopterin	-	?

Organism

Organism	UniProt	Comment	Textmining
Archaeoglobus fulgidus	O28344	-	-

Purification (Commentary)

Purification (Comment)	Organism
-	Archaeoglobus fulgidus

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
5,10-methenyl-5,6,7,8-tetrahydromethanopterin + H2O	-	Archaeoglobus fulgidus	5-formyl-5,6,7,8-tetrahydromethanopterin	-	?
5,10-methenyl-5,6,7,8-tetrahydromethanopterin + H2O	the active site is primarily built up by the segment 93:95, Arg183 and Glu186 that either interact with the catalytic water attacking 5,10-methenyl-5,6,7,8-tetrahydromethanopterin or with the formyl oxygen of 5-formyl-5,6,7,8-tetrahydromethanopterin. The catalytic function of the strictly conserved Arg183 and Glu186 is substantiated by the low enzymatic activities of the E186A, E186D, E186N, E186Q, R183A, R183Q, R183E, R183K, and R183E-E186Q variants. Glu186 most likely acts as a general base. Arg183 decisively influences the pKa value of Glu186 and the proposed catalytic water mainly by its positive charge. In addition, Glu186 appears to be also responsible for product specificity by donating a proton to the directly neighbored N10 tertiary amine of H4MPT. Thus, N10 becomes a better leaving group than N5 which implies the generation of 5-formyl-5,6,7,8-tetrahydromethanopterin	Archaeoglobus fulgidus	5-formyl-5,6,7,8-tetrahydromethanopterin	-	?

Synonyms

Synonyms	Comment	Organism
Mch	-	Archaeoglobus fulgidus
methenyl-H4MPT+ cyclohydrolase	-	Archaeoglobus fulgidus
methenyltetrahydromethanopterin cyclohydrolase	-	Archaeoglobus fulgidus

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
65	-	assay at	Archaeoglobus fulgidus

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7.6	-	assay at	Archaeoglobus fulgidus

General Information

General Information	Comment	Organism
physiological function	the enzyme catalyzes a reaction in the one-carbon energy metabolism of methanogenic, methanotrophic, and sulfate-reducing archaea and of methylotrophic bacteria	Archaeoglobus fulgidus

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Release 2023.1 (January 2023)