PDBsum entry 2a8y

Transferase

PDB id: 2a8y

Contents

Protein chains

(+ 6 more) 263 a.a. *

Ligands

SO4 ×24

MTA ×12

Waters ×3405

* Residue conservation analysis

PDB id:

2a8y

Name:

Transferase

Title:

Crystal structure of 5'-deoxy-5'methylthioadenosine phosphorylase complexed with 5'-deoxy-5'methylthioadenosine and sulfate

Structure:

5'-methylthioadenosine phosphorylase (mtap). Chain: a, b, c, d, e, f, g, h, i, j, k, l. Engineered: yes

Source:

Sulfolobus solfataricus. Organism_taxid: 2287. Gene: ssmtapii. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Hexamer (from PQS)

Resolution:

1.45Å R-factor: 0.182 R-free: 0.202

Authors:

Y.Zhang,M.Porcelli,G.Cacciapuoti,S.E.Ealick

Key ref:

Y.Zhang et al. (2006). The crystal structure of 5'-deoxy-5'-methylthioadenosine phosphorylase II from Sulfolobus solfataricus, a thermophilic enzyme stabilized by intramolecular disulfide bonds. J Mol Biol, 357, 252-262. PubMed id: 16414070 DOI: 10.1016/j.jmb.2005.12.040

Date:

10-Jul-05 Release date: 28-Mar-06

Protein chains

Q97W94  (MTAP_SULSO) -  S-methyl-5'-thioadenosine phosphorylase from Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)

Seq: 270 a.a.

Struc: 263 a.a.

Enzyme reactions

• Enzyme class: E.C.2.4.2.28 - S-methyl-5'-thioadenosine phosphorylase.
• Reaction: S-methyl-5'-thioadenosine + phosphate = 5-(methylsulfanyl)-alpha-D-ribose 1-phosphate + adenine

S-methyl-5'-thioadenosine + phosphate (Bound ligand (Het Group name = MTA) corresponds exactly) = 5-(methylsulfanyl)-alpha-D-ribose 1-phosphate + adenine

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1016/j.jmb.2005.12.040

J Mol Biol 357:252-262 (2006)

PubMed id: 16414070

The crystal structure of 5'-deoxy-5'-methylthioadenosine phosphorylase II from Sulfolobus solfataricus, a thermophilic enzyme stabilized by intramolecular disulfide bonds.

Y.Zhang, M.Porcelli, G.Cacciapuoti, S.E.Ealick.

ABSTRACT

The crystal structure of Sulfolobus solfataricus 5'-deoxy-5'-methylthioadenosine phosphorylase II (SsMTAPII) in complex with 5'-deoxy-5'-methylthioadenosine (MTA) and sulfate was determined to 1.45A resolution. The hexameric structure of SsMTAPII is a dimer-of-trimers with one active site per monomer. The oligomeric assembly of the trimer and the monomer topology of SsMTAPII are almost identical with trimeric human 5'-deoxy-5'-methylthioadenosine phosphorylase (hMTAP). SsMTAPII is the first reported hexameric member in the trimeric class of purine nucleoside phosphorylase (PNP) from Archaea. Unlike hMTAP, which is highly specific for MTA, SsMTAPII also accepts adenosine as a substrate. The residues at the active sites of SsMTAPII and hMTAP are almost identical. The broad substrate specificity of SsMTAPII may be due to the flexibility of the C-terminal loop. SsMTAPII is extremely thermoactive and thermostable. The three-dimensional structure of SsMTAPII suggests that the unique dimer-of-trimers quaternary structure, a CXC motif at the C terminus, and two pairs of intrasubunit disulfide bridges may play an important role in its thermal stability.

Selected figure(s)

Figure 2.
Figure 2. Structure of the SsMTAPII subunit. (a) A ribbon diagram representing the secondary structural elements in the SsMTAPII subunit (a helices, blue; b strands, green). The substrate MTA and sulfate are shown in ball-and-stick representation. The disordered loop composed of residues 255-261 is shown as a dotted line. (b) Topology diagram. The a helices are shown as blue rectangles, and the b strands are shown as green arrows. Each secondary structural element is labeled in its center with its designator and with its beginning and ending sequence number.

Figure 5.
Figure 5. Schematic representation of the SsMTAPII active site. Residues of SsMTAPII are shown in black boxes. Residues in red boxes identify structurally equivalent residues in human MTAP. Residues in blue boxes represent structurally equivalent residues in human PNP. An asterisk designates residues from the neighboring subunit. Key hydrogen bonds are indicated by broken lines with the corresponding donor-acceptor distance labeled.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2006, 357, 252-262) copyright 2006.

Figures were selected by an automated process.