Literature summary for 3.2.2.16 extracted from

Kim, R.Q.; Offen, W.A.; Davies, G.J.; Stubbs, K.A.
Structural enzymology of Helicobacter pylori methylthioadenosine nucleosidase in the futalosine pathway (2014), Acta Crystallogr. Sect. D, 70, 177-185.

Application

Application	Comment	Organism
drug development	the enzyme is a potential target for specific antibiotics	Helicobacter pylori

Cloned(Commentary)

Cloned (Comment)	Organism
expressed in Escherichia coli BL21(DE3) cells	Helicobacter pylori
gene mnqB, expression of recombinant His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21 (DE3)	Helicobacter pylori

Crystallization (Commentary)

Crystallization (Comment)	Organism
purified recombinant wild-type and mutant enzymes, sitting drop vapour diffusion method, mixing of 50 mg/ml protein in 10 mM Tris-HCl, pH 8.0, with 4.0 M NaH2PO4/K2HPO4, pH 7.0, using a 1:1 ratio of protein to mother liquor, X-ray diffraction structure determination and analysis at 1.65-2.11 A resolution, molecular replacement. for the mutant enzymess th following crystallization slutions are used: for E14Q 0.1 M HEPES, pH 7.5, 25% PEG 3350, 0.2 M NaCl, for D199N 0.1 M bis-Tris, pH 5.5, 25% PEG 3350, 0.2 M MgCl2 x 6H2O, and for D199A 0.1 M bis-Tris, pH 6.5, 25% PEG 3350, 0.2 M Li2SO4 xH2O	Helicobacter pylori
sitting drop vapor diffusion method, over 4.0 M NaH2PO4/K2HPO4 pH 7.0	Helicobacter pylori

Crystallization (Comment)

Organism

purified recombinant wild-type and mutant enzymes, sitting drop vapour diffusion method, mixing of 50 mg/ml protein in 10 mM Tris-HCl, pH 8.0, with 4.0 M NaH2PO4/K2HPO4, pH 7.0, using a 1:1 ratio of protein to mother liquor, X-ray diffraction structure determination and analysis at 1.65-2.11 A resolution, molecular replacement. for the mutant enzymess th following crystallization slutions are used: for E14Q 0.1 M HEPES, pH 7.5, 25% PEG 3350, 0.2 M NaCl, for D199N 0.1 M bis-Tris, pH 5.5, 25% PEG 3350, 0.2 M MgCl2 x 6H2O, and for D199A 0.1 M bis-Tris, pH 6.5, 25% PEG 3350, 0.2 M Li2SO4 xH2O

Helicobacter pylori

sitting drop vapor diffusion method, over 4.0 M NaH2PO4/K2HPO4 pH 7.0

Helicobacter pylori

Protein Variants

Protein Variants	Comment	Organism
D199A	site-directed mutagenesis, structure determination and comparison to the wild-type enzyme	Helicobacter pylori
D199A	the enzyme shows minor activity towards 6-amino-6-deoxyfutalosine	Helicobacter pylori
D199N	inactive	Helicobacter pylori
D199N	site-directed mutagenesis, structure determination and comparison to the wild-type enzyme	Helicobacter pylori
E14A	inactive	Helicobacter pylori
E14Q	site-directed mutagenesis, structure determination and comparison to the wild-type enzyme	Helicobacter pylori
E14Q	the enzyme shows minor activity towards 6-amino-6-deoxyfutalosine	Helicobacter pylori

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.
5'-methylthioadenosine + H2O	Helicobacter pylori	-	adenine + S-methyl-5-thio-D-ribose	-	?
6-amino-6-deoxyfutalosine + H2O	Helicobacter pylori	-	3-{3-[(2R,3S,4R,5R)-3,4,5-trihydroxytetrahydrofuran-2-yl]propanoyl}benzoic acid + 9H-purine-6-amine	-	?
S-methyl-5'-thioadenosine + H2O	Helicobacter pylori	-	S-methyl-5-thio-D-ribose + adenine	-	?

Organism

Organism	UniProt	Comment	Textmining
Helicobacter pylori	O24915	-	-
Helicobacter pylori	O24915	gene mnqB	-

Purification (Commentary)

Purification (Comment)	Organism
HisTrap column chromatography and Superdex 75 gel filtration	Helicobacter pylori
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain BL21 (DE3) by nickel affinity chromatography and gel filtration	Helicobacter pylori

Reaction

Reaction	Comment	Organism	Reaction ID
S-methyl-5'-thioadenosine + H2O = S-methyl-5-thio-D-ribose + adenine	structure-function analysis and reaction mechanism, overview. The proposed mechanism of action for the hydrolysis of methylthioadenosine by the enzyme involves the essential acidic residue in the lid of the active site and a water molecule that acts as a nucleophile which is activated by an arginine and a glutamic acid residue	Helicobacter pylori	a

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
5'-methylthioadenosine + H2O	-	Helicobacter pylori	adenine + S-methyl-5-thio-D-ribose	-	?
6-amino-6-deoxyfutalosine + H2O	-	Helicobacter pylori	3-{3-[(2R,3S,4R,5R)-3,4,5-trihydroxytetrahydrofuran-2-yl]propanoyl}benzoic acid + 9H-purine-6-amine	-	?
6-amino-6-deoxyfutalosine + H2O	-	Helicobacter pylori	adenine + dehypoxanthinyl futalosine	-	?
additional information	broad substrate specificity	Helicobacter pylori	?	-	?
S-methyl-5'-thioadenosine + H2O	-	Helicobacter pylori	S-methyl-5-thio-D-ribose + adenine	-	?

Subunits

Subunits	Comment	Organism
homodimer	x-ray crystallography	Helicobacter pylori

Synonyms

Synonyms	Comment	Organism
5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase	-	Helicobacter pylori
50-methylthioadenosine/S-adenosylhomocysteine nucleosidase	-	Helicobacter pylori
HpyMqnB	-	Helicobacter pylori
methylthioadenosine nucleosidase	-	Helicobacter pylori
MqnB	-	Helicobacter pylori
MTAN	-	Helicobacter pylori

General Information

General Information	Comment	Organism
metabolism	the enzyme is involved in the second step of the futalosine pathway, which is crucial for the biosynthesis of the essential prokaryotic respiratory compound menaquinone, which is a key molecule in the bacterial respiratory pathway and a lipid-soluble electron carrier known in eukaryotes as vitamin K2, overview	Helicobacter pylori
additional information	active site structure involving E14 and D199, overview	Helicobacter pylori