Literature summary for 2.4.2.28 extracted from

Park, E.Y.; Choi, W.S.; Oh, S.I.; Kim, K.N.; Shin, J.S.; Song, H.K.
Biochemical and structural characterization of 5-methylthioadenosine nucleosidases from Arabidopsis thaliana (2009), Biochem. Biophys. Res. Commun., 381, 619-624.

Cloned(Commentary)

Cloned (Comment)	Organism
into pGEX-4T3 vector and overexpressed in Escherichia coli BL21 (DE3) RIL	Arabidopsis thaliana

Crystallization (Commentary)

Crystallization (Comment)	Organism
in complex with adenine, by sitting- and hanging-drop formation at 22°C, at 2.9 A resolution. Belongs to space group P3121, monomer consists of seven alpha-helices, ten beta-strands, and a 3(10)-helix. Residues between 216 and 225 demonstrate weak electron density for both subunits, therefore indicating this loop has high flexibility. Bound adenine is located in the deep pocket formed by the monomer with the entrance partially covered by the adjacent subunit. This flap is critical in the formation of a wide dimer interface	Arabidopsis thaliana

Crystallization (Comment)

Organism

in complex with adenine, by sitting- and hanging-drop formation at 22°C, at 2.9 A resolution. Belongs to space group P3121, monomer consists of seven alpha-helices, ten beta-strands, and a 3(10)-helix. Residues between 216 and 225 demonstrate weak electron density for both subunits, therefore indicating this loop has high flexibility. Bound adenine is located in the deep pocket formed by the monomer with the entrance partially covered by the adjacent subunit. This flap is critical in the formation of a wide dimer interface

Arabidopsis thaliana

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
0.0276	-	5'-methylthioadenosine	-	Arabidopsis thaliana
0.0334	-	5'-methylthioadenosine	-	Arabidopsis thaliana
0.2009	-	S-adenosylhomocysteine	-	Arabidopsis thaliana

Organism

Organism	UniProt	Comment	Textmining
Arabidopsis thaliana	Q7XA67	-	-
Arabidopsis thaliana	Q9T0I8	-	-

Purification (Commentary)

Purification (Comment)	Organism
by ultrasonication, centrifugation, gel filtration and anion exchange chromatography, to homogeneity	Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
5'-methylthioadenosine + phosphate	adenine-bound MTAN1 is exclusively in its closed form, substantial conformational changes occur in this region during the enzymatic reaction. Residues Met35, Val90, Leu181, Met201, Phe237 and Ile143', Ile145' and Phe148' in a neighboring MTAN1 monomer bind adenine via hydrophobic and van der Waals interactions. The hydrophobic side chains Phe237 and Leu181 show structural perturbations that provide the flexible accommodation of the adenine ring. The carboxylic side chain of Asp225 hydrogen bonds with nitrogen atoms in the adenine ring, therefore being key determinant for the adenine base. The side chain Thr116 and backbone Gly118 also interact with the adenine molecule	Arabidopsis thaliana	adenine + 5-methylthio-D-ribose 1-phosphate	-	?
5'-methylthioadenosine + phosphate	hydrolysis of 5'-methylthioadenosine predominates despite MTAN2 possessing both 5'-methylthioadenosine and S-adenosylhomocysteine hydrolysis activity. MTAN2 binds 5'-methylthioadenosine approximately 6fold higher than S-adenosylhomocysteine. Residues between 216 and 225 in MTAN2 contain conformational differences representing an open conformation when compared with MTAN1. The side chains Met22, Val78, Met168, Met188, Phe224 along with Ile130', Val132' and Leu135' in a neighboring MTAN2 monomer bind adenine via hydrophobic and van der Waals interactions. The hydrophobic side chains Phe224 and Met168 show structural perturbations that provide the flexible accommodation of the adenine ring. The carboxylic side chain of Asp211 hydrogen bonds with nitrogen atoms in the adenine ring, therefore being key determinant for the adenine base. The side chain Thr103 and backbone Gly105 also interact with the adenine molecule	Arabidopsis thaliana	adenine + 5-methylthio-D-ribose 1-phosphate	-	?
additional information	can not hydrolyze S-adenosylhomocysteine	Arabidopsis thaliana	?	-	?
S-adenosylhomocysteine + ?	-	Arabidopsis thaliana	?	-	?

Subunits

Subunits	Comment	Organism
dimer	gel filtration	Arabidopsis thaliana

Synonyms

Synonyms	Comment	Organism
5'-methylthioadenosine nucleosidase	-	Arabidopsis thaliana
MTAN1	-	Arabidopsis thaliana
MTAN2	-	Arabidopsis thaliana