PDBsum entry 1i2d

Transferase

PDB id: 1i2d

Contents

Protein chains

572 a.a. *

Ligands

ADX ×6

Waters ×282

* Residue conservation analysis

PDB id:

1i2d

Name:

Transferase

Title:

Crystal structure of atp sulfurylase from penicillium chrysogenum

Structure:

Atp sulfurylase. Chain: a, b, c. Synonym: sulfate adenylyltransferase. Engineered: yes

Source:

Penicillium chrysogenum. Organism_taxid: 5076. Gene: aps. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Hexamer (from PDB file)

Resolution:

2.81Å R-factor: 0.207 R-free: 0.245

Authors:

I.J.Macrae,I.H.Segel,A.J.Fisher

Key ref:

I.J.MacRae et al. (2001). Crystal structure of ATP sulfurylase from Penicillium chrysogenum: insights into the allosteric regulation of sulfate assimilation. Biochemistry, 40, 6795-6804. PubMed id: 11389593 DOI: 10.1021/bi010367w

Date:

07-Feb-01 Release date: 11-Jul-01

Protein chains

Q12650  (MET3_PENCH) -  Sulfate adenylyltransferase from Penicillium chrysogenum

Seq: 572 a.a.

Struc: 572 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.2.7.7.4 - sulfate adenylyltransferase.
• Reaction: sulfate + ATP + H⁺ = adenosine 5'-phosphosulfate + diphosphate

sulfate + ATP + H(+) = adenosine 5'-phosphosulfate (Bound ligand (Het Group name = ADX) corresponds exactly) + diphosphate

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

reference

DOI no: 10.1021/bi010367w

Biochemistry 40:6795-6804 (2001)

PubMed id: 11389593

Crystal structure of ATP sulfurylase from Penicillium chrysogenum: insights into the allosteric regulation of sulfate assimilation.

I.J.MacRae, I.H.Segel, A.J.Fisher.

ABSTRACT

ATP sulfurylase from Penicillium chrysogenum is an allosterically regulated enzyme composed of six identical 63.7 kDa subunits (573 residues). The C-terminal allosteric domain of each subunit is homologous to APS kinase. In the presence of APS, the enzyme crystallized in the orthorhombic space group (I222) with unit cell parameters of a = 135.7 A, b = 162.1 A, and c = 273.0 A. The X-ray structure at 2.8 A resolution established that the hexameric enzyme is a dimer of triads in the shape of an oblate ellipsoid 140 A diameter x 70 A. Each subunit is divided into a discreet N-terminal domain, a central catalytic domain, and a C-terminal allosteric domain. Two molecules of APS bound per subunit clearly identify the catalytic and allosteric domains. The sequence 197QXRN200 is largely responsible for anchoring the phosphosulfate group of APS at the active site of the catalytic domain. The specificity of the catalytic site for adenine nucleotides is established by specific hydrogen bonds to the protein main chain. APS was bound to the allosteric site through sequence-specific interactions with amino acid side chains that are conserved in true APS kinase. Within a given triad, the allosteric domain of one subunit interacts with the catalytic domain of another. There are also allosteric-allosteric, allosteric-N-terminal, and catalytic-catalytic domain interactions across the triad interface. The overall interactions-each subunit with four others-provide stability to the hexamer as well as a way to propagate a concerted allosteric transition. The structure presented here is believed to be the R state. A solvent channel, 15-70 A wide exists along the 3-fold axis, but substrates have access to the catalytic site only from the external medium. On the other hand, a surface "trench" links each catalytic site in one triad with an allosteric site in the other triad. This trench may be a vestigial feature of a bifunctional ("PAPS synthetase") ancestor of fungal ATP sulfurylase.