P0AF12 (MTNN_ECOLI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase
Short name=MTA/SAH nucleosidase
Short name=MTAN
EC=3.2.2.9

Alternative name(s):
5'-methylthioadenosine nucleosidase
Short name=MTA nucleosidase
P46
S-adenosylhomocysteine nucleosidase
Short name=AdoHcy nucleosidase
Short name=SAH nucleosidase
Short name=SRH nucleosidase

Gene names

Name:	mtnN
Synonyms:	mtn, pfs, yadA
Ordered Locus Names:	b0159, JW0155

Organism

Escherichia coli (strain K12) [Reference proteome] [HAMAP]

Taxonomic identifier

83333 [NCBI]

Taxonomic lineage

cellular organisms › Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Escherichia › Escherichia coli

Protein attributes

Sequence length	232 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Catalyzes the irreversible cleavage of the glycosidic bond in both 5'-methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH/AdoHcy) to adenine and the corresponding thioribose, 5'-methylthioribose and S-ribosylhomocysteine, respectively. Can also use 5'-isobutylthioadenosine, 5'-n-butylthioadenosine, S-adenosyl-D-homocysteine, decarboxylated adenosylhomocysteine, deaminated adenosylhomocysteine and S-2-aza-adenosylhomocysteine as substrates. HAMAP-Rule MF_01684
Catalytic activity	S-adenosyl-L-homocysteine + H2O = S-(5-deoxy-D-ribos-5-yl)-L-homocysteine + adenine. HAMAP-Rule MF_01684 S-methyl-5'-thioadenosine + H2O = S-methyl-5-thio-D-ribose + adenine. HAMAP-Rule MF_01684
Enzyme regulation	Strongly inhibited by aryl-substituted MTA analogs, alkyl-substituted MTA analogs, 5'-methylthioformycin, 5'-chloroformycin, S-formycinylhomocysteine, 5'-methylthiotubercidin, S-tubercidinylhomocysteine and S-8-aza-adenosylhomocysteine. Poorly inhibited by 5'-isobutylthioinosine, 5'-n-butylthioinosine, 5'-methylthio-3-deaza-adenosine, 5'-isobutylthio-3-deaza-adenosine, S-n-6-methyl-3-deaza-adenosylhomocysteine, S-adenosylhomocysteine sulphoxide and Sinefungin. Ref.7 Ref.8 Ref.11 Ref.12
Pathway	Amino-acid biosynthesis; L-methionine biosynthesis via salvage pathway; S-methyl-5-thio-alpha-D-ribose 1-phosphate from S-methyl-5'-thioadenosine (hydrolase route): step 1/2. HAMAP-Rule MF_01684
Subunit structure	Homodimer. Ref.10
Sequence similarities	Belongs to the PNP/UDP phosphorylase family. MtnN subfamily.
Biophysicochemical properties	Kinetic parameters: KM=0.43 µM for 5'-methylthioadenosine (at pH 7 and 37 degrees Celsius) Ref.7 Ref.8 KM=4.3 µM for S-adenosylhomocysteine (at pH 7 and 37 degrees Celsius) Vmax=373 µmol/min/mg enzyme with 5'-methylthioadenosine as substrate (at pH 7 and 37 degrees Celsius) Vmax=156 µmol/min/mg enzyme with S-adenosylhomocysteine as substrate (at pH 7 and 37 degrees Celsius) pH dependence: Exhibits activity across a broad pH range. Enzyme activity is moderately improved under acidic conditions. Temperature dependence: Optimum temperature is 37-45 degrees Celsius. Rapidly inactivated after exposure for 10 min at 55 degrees Celsius.
Sequence caution	The sequence AAA23678.1 differs from that shown. Reason: Erroneous initiation.

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Methionine biosynthesis
Molecular function	Hydrolase
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	L-methionine biosynthetic process from S-adenosylmethionine Inferred from direct assay Ref.2. Source: EcoCyc L-methionine salvage from methylthioadenosine Inferred from electronic annotation. Source: UniProtKB-UniPathway generation of a signal involved in cell-cell signaling Inferred from direct assay PubMed 11489131. Source: EcoCyc nucleoside catabolic process Inferred from electronic annotation. Source: InterPro
Molecular_function	adenosylhomocysteine nucleosidase activity Inferred from direct assay Ref.2. Source: EcoCyc methylthioadenosine nucleosidase activity Inferred from direct assay Ref.2. Source: EcoCyc
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 232

232

5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase HAMAP-Rule MF_01684

PRO_0000164439

Regions

Region

173 – 174

2

Substrate binding HAMAP-Rule MF_01684

Sites

Active site

12

1

Proton acceptor Probable

Binding site

78

1

Substrate; via amide nitrogen

Binding site

152

1

Substrate; via amide nitrogen and carbonyl oxygen

Binding site

197

1

Substrate

Experimental info

Mutagenesis

12

1

E → Q: Loss of nucleosidase activity. Ref.13

Mutagenesis

197

1

D → N: Alters the hydrogen bond network in the active site. Ref.13

Sequence conflict

212 – 232

21

AVAAK…KLAHG → LLPLNSPA in AAA23678. Ref.1

Sequence conflict

212 – 232

21

AVAAK…KLAHG → LLPLNSPA in AAA24322. Ref.1

Secondary structure

1

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232

Helix Strand Turn

Details...

Beta strand

2 – 9

8

Helix

10 – 17

8

Beta strand

21 – 28

8

Beta strand

31 – 38

8

Beta strand

41 – 47

7

Helix

52 – 66

15

Beta strand

69 – 79

11

Beta strand

89 – 99

11

Helix

103 – 105

3

Beta strand

117 – 120

4

Helix

123 – 135

13

Beta strand

140 – 147

8

Helix

155 – 164

10

Beta strand

168 – 174

7

Helix

175 – 185

11

Beta strand

189 – 197

9

Helix

203 – 231

29

Sequences

	Sequence		Length	Mass (Da)
	P0AF12 [UniParc]. Last modified December 20, 2005. Version 1. Checksum: 9B1FF9BEC39D4F2C	FASTA	232	24,354
	10 20 30 40 50 60 MKIGIIGAME EEVTLLRDKI ENRQTISLGG CEIYTGQLNG TEVALLKSGI GKVAAALGAT 70 80 90 100 110 120 LLLEHCKPDV IINTGSAGGL APTLKVGDIV VSDEARYHDA DVTAFGYEYG QLPGCPAGFK 130 140 150 160 170 180 ADDKLIAAAE ACIAELNLNA VRGLIVSGDA FINGSVGLAK IRHNFPQAIA VEMEATAIAH 190 200 210 220 230 VCHNFNVPFV VVRAISDVAD QQSHLSFDEF LAVAAKQSSL MVESLVQKLA HG

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Structure and regulation of the gene for dGTP triphosphohydrolase from Escherichia coli." Wurgler S.M., Richardson C.C. Proc. Natl. Acad. Sci. U.S.A. 87:2740-2744(1990) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: K12.
[2]	"Cloning and expression of Escherichia coli 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase: identification of the pfs gene product." Cornell K.A., Riscoe M.K. Biochim. Biophys. Acta 1396:8-14(1998) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], CHARACTERIZATION.
[3]	"Systematic sequencing of the Escherichia coli genome: analysis of the 2.4-4.1 min (110,917-193,643 bp) region." Fujita N., Mori H., Yura T., Ishihama A. Nucleic Acids Res. 22:1637-1639(1994) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[4]	"Sequence of minutes 4-25 of Escherichia coli." Chung E., Allen E., Araujo R., Aparicio A.M., Davis K., Duncan M., Federspiel N., Hyman R., Kalman S., Komp C., Kurdi O., Lew H., Lin D., Namath A., Oefner P., Roberts D., Schramm S., Davis R.W. Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[5]	"The complete genome sequence of Escherichia coli K-12." Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., Shao Y. Science 277:1453-1474(1997) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[6]	"Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110." Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T. Mol. Syst. Biol. 2:E1-E5(2006) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[7]	"Escherichia coli S-adenosylhomocysteine/5'-methylthioadenosine nucleosidase. Purification, substrate specificity and mechanism of action." Della Ragione F., Porcelli M., Carteni-Farina M., Zappia V., Pegg A.E. Biochem. J. 232:335-341(1985) [PubMed] [Europe PMC] [Abstract] Cited for: BIOPHYSICOCHEMICAL PROPERTIES, ENZYME REGULATION.
[8]	"Characterization of recombinant Eschericha coli 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase: analysis of enzymatic activity and substrate specificity." Cornell K.A., Swarts W.E., Barry R.D., Riscoe M.K. Biochem. Biophys. Res. Commun. 228:724-732(1996) [PubMed] [Europe PMC] [Abstract] Cited for: BIOPHYSICOCHEMICAL PROPERTIES, ENZYME REGULATION.
[9]	"Escherichia coli proteome analysis using the gene-protein database." VanBogelen R.A., Abshire K.Z., Moldover B., Olson E.R., Neidhardt F.C. Electrophoresis 18:1243-1251(1997) [PubMed] [Europe PMC] [Abstract] Cited for: IDENTIFICATION BY 2D-GEL.
[10]	"Structure of E. coli 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase reveals similarity to the purine nucleoside phosphorylases." Lee J.E., Cornell K.A., Riscoe M.K., Howell P.L. Structure 9:941-953(2001) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS) IN COMPLEX WITH SUBSTRATE, SUBUNIT.
[11]	"Structure of Escherichia coli 5'-methylthioadenosine/ S-adenosylhomocysteine nucleosidase inhibitor complexes provide insight into the conformational changes required for substrate binding and catalysis." Lee J.E., Cornell K.A., Riscoe M.K., Howell P.L. J. Biol. Chem. 278:8761-8770(2003) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) IN COMPLEX WITH SUBSTRATE ANALOGS, ENZYME REGULATION.
[12]	"Femtomolar transition state analogue inhibitors of 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase from Escherichia coli." Singh V., Evans G.B., Lenz D.H., Mason J.M., Clinch K., Mee S., Painter G.F., Tyler P.C., Furneaux R.H., Lee J.E., Howell P.L., Schramm V.L. J. Biol. Chem. 280:18265-18273(2005) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS) IN COMPLEX WITH SUBSTRATE ANALOGS, ENZYME REGULATION.
[13]	"Structural snapshots of MTA/AdoHcy nucleosidase along the reaction coordinate provide insights into enzyme and nucleoside flexibility during catalysis." Lee J.E., Smith G.D., Horvatin C., Huang D.J., Cornell K.A., Riscoe M.K., Howell P.L. J. Mol. Biol. 352:559-574(2005) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.1 ANGSTROMS) IN COMPLEX WITH SUBSTRATE ANALOGS, MUTANTS GLN-197 AND GLN-12, REACTION MECHANISM, MUTAGENESIS OF GLU-12 AND ASP-197.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

M31772 Genomic DNA. Translation: AAA23678.1. Different initiation.
U24438 Genomic DNA. Translation: AAC38291.1.
M83735 Genomic DNA. Translation: AAA24322.1.
U70214 Genomic DNA. Translation: AAB08589.1.
U00096 Genomic DNA. Translation: AAC73270.1.
AP009048 Genomic DNA. Translation: BAB96736.1.

PIR

S45227.

RefSeq

NP_414701.1. NC_000913.2.
YP_488462.1. NC_007779.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1JYS	X-ray	1.90	A/B	1-232	[»]
1NC1	X-ray	2.00	A/B	1-232	[»]
1NC3	X-ray	2.20	A/B	1-232	[»]
1Y6Q	X-ray	2.20	A/B	1-232	[»]
1Y6R	X-ray	2.20	A/B	1-232	[»]
1Z5N	X-ray	2.10	A/B	1-232	[»]
1Z5O	X-ray	2.00	A/B	1-232	[»]
1Z5P	X-ray	2.00	A	1-232	[»]
3O4V	X-ray	1.75	A/B	1-232	[»]

ProteinModelPortal

P0AF12.

SMR

P0AF12. Positions 1-232.

ModBase

Search...

Protein-protein interaction databases

IntAct

P0AF12. 6 interactions.

STRING

511145.b0159.

2D gel databases

SWISS-2DPAGE

P0AF12.

Proteomic databases

PaxDb

P0AF12.

PRIDE

P0AF12.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblBacteria

AAC73270; AAC73270; b0159.
BAB96736; BAB96736; BAB96736.

GeneID

12931997.
948542.

KEGG

ecj:Y75_p0156.
eco:b0159.

PATRIC

32115427. VBIEscCol129921_0165.

Organism-specific databases

EchoBASE

EB1082.

EcoGene

EG11090. pfs.

Phylogenomic databases

eggNOG

COG0775.

HOGENOM

HOG000259346.

KO

K01243.

OMA

QRAGCEI.

ProtClustDB

PRK05584.

Enzyme and pathway databases

BioCyc

EcoCyc:EG11090-MONOMER.
ECOL316407:JW0155-MONOMER.
MetaCyc:EG11090-MONOMER.

UniPathway

UPA00904; UER00871.

Gene expression databases

Genevestigator

P0AF12.

Family and domain databases

HAMAP

MF_01684. Salvage_tnN.

InterPro

IPR010049. MTA_SAH_Nsdase.
IPR018017. Nucleoside_phosphorylase.
IPR000845. Nucleoside_phosphorylase_d.
[Graphical view]

PANTHER

PTHR21234. PTHR21234. 1 hit.
PTHR21234:SF6. PTHR21234:SF6. 1 hit.

Pfam

PF01048. PNP_UDP_1. 1 hit.
[Graphical view]

TIGRFAMs

TIGR01704. MTA/SAH-Nsdase. 1 hit.

ProtoNet

Search...

Other

BindingDB

P0AF12.

ChEMBL

CHEMBL2866.

DrugBank

DB00173. Adenine.

EvolutionaryTrace

P0AF12.

Entry information

Entry name

MTNN_ECOLI

Accession

Primary (citable) accession number: P0AF12
Secondary accession number(s): P24247

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 20, 2005
Last sequence update:	December 20, 2005
Last modified:	May 1, 2013
This is version 76 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program