Reviewed, UniProtKB/Swiss-Prot Q9R4A1 (MTNN_KLEPN)

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
    S-adenosylhomocysteine nucleosidase
      Short name=SAH nucleosidase
      Short name=AdoHcy nucleosidase
      Short name=SRH nucleosidase

Gene names

Name:

mtnN

Organism

Klebsiella pneumoniae

Taxonomic identifier

573 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Klebsiella

Protein attributes

Sequence length	35 AA.
Sequence status	Fragment.
Sequence processing	The displayed sequence is not processed.
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. HAMAP MF_01684
Catalytic activity	S-adenosyl-L-homocysteine + H2O = S-(5-deoxy-D-ribos-5-yl)-L-homocysteine + adenine. HAMAP MF_01684 S-methyl-5'-thioadenosine + H2O = S-methyl-5-thio-D-ribose + adenine. HAMAP MF_01684
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 MF_01684
Subunit structure	Homodimer By similarity.
Sequence similarities	Belongs to the PNP/UDP phosphorylase family. MtnN subfamily.
Biophysicochemical properties	Kinetic parameters: KM=8.7 µM for 5'-methylthioadenosine (at pH 7 and 37 degrees Celsius) HAMAP MF_01684

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Methionine biosynthesis
Molecular function	Hydrolase
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	methionine biosynthetic process from S-adenosylmethionine Inferred from electronic annotation. Source: HAMAP
Molecular function	adenosylhomocysteine nucleosidase activity Inferred from electronic annotation. Source: HAMAP methylthioadenosine nucleosidase activity Inferred from electronic annotation. Source: HAMAP
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – ›35	›35	5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase HAMAP MF_01684		PRO_0000359310
Sites
	Active site	12	1	Proton acceptor By similarity
Experimental info
	Non-terminal residue	35	1

Sequences

	Sequence		Length	Mass (Da)
	Q9R4A1-1 [UniParc]. Last modified May 1, 2000. Version 1. Checksum: FB878C0271A01C35	FASTA	35	3,924
	10 20 30 MKIGIIGAME EEVTLLRDKI ENRQTITIGG SEIYT

References

[1]

"Affinity purification of 5-methylthioribose kinase and 5-methylthioadenosine/S-adenosylhomocysteine nucleosidase from Klebsiella pneumoniae." Cornell K.A., Winter R.W., Tower P.A., Riscoe M.K. Biochem. J. 317:285-290(1996) [PubMed: 8694776] [Abstract] Cited for: PROTEIN SEQUENCE, BIOPHYSICOCHEMICAL PROPERTIES.

Cross-references

3D structure databases
HSSP	HSSP built from PDB template 1NC1 based on UniProtKB P24247.
ModBase	Search...
Enzyme and pathway databases
BioCyc	MetaCyc:MON-1288.
Family and domain databases
HAMAP	MF_01684. [Tree]
ProtoNet	Search...

Entry information

Entry name

MTNN_KLEPN

Accession

Primary (citable) accession number: Q9R4A1

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 20, 2009
Last sequence update:	May 1, 2000
Last modified:	September 22, 2009
This is version 26 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)