PDBsum entry 4jd0

Transferase

PDB id: 4jd0

Contents

Protein chain

245 a.a.

Ligands

1KH

PO4 ×3

GOL ×2

Metals

_NA ×8

_CL

Waters ×240

PDB id:

4jd0

Name:

Transferase

Title:

Structure of the inositol-1-phosphate ctp transferase from t. Maritima.

Structure:

Nucleotidyl transferase. Chain: a. Engineered: yes

Source:

Thermotoga maritima. Organism_taxid: 243274. Strain: atcc 43589 / msb8 / dsm 3109 / jcm 10099. Gene: themadraft_0946, tm1418a. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.80Å R-factor: 0.114 R-free: 0.166

Authors:

B.Stec

Key ref:

O.V.Kurnasov et al. (2013). Structure of the inositol-1-phosphate cytidylyltransferase from Thermotoga maritima. Acta Crystallogr D Biol Crystallogr, 69, 1808-1817. PubMed id: 23999304 DOI: 10.1107/S0907444913015278

Date:

22-Feb-13 Release date: 18-Sep-13

Protein chain

G4FFF4  (G4FFF4_THEMA) -

DOI no: 10.1107/S0907444913015278

Acta Crystallogr D Biol Crystallogr 69:1808-1817 (2013)

PubMed id: 23999304

Structure of the inositol-1-phosphate cytidylyltransferase from Thermotoga maritima.

O.V.Kurnasov, H.J.Luk, M.F.Roberts, B.Stec.

ABSTRACT

The unique steps in the synthesis of an unusual osmolyte in hyperthermophiles, di-myo-inositol-1,1'-phosphate (DIP), involve the production of CDP-inositol and its condensation with an inositol-1-phosphate molecule to form phosphorylated DIP. While many organisms fuse both activities into a single enzyme, the two are separate in Thermotoga maritima. The crystal structure of the T. maritima inositol-1-phosphate cytidylyltransferase, which as a soluble protein may transiently associate with its membrane-embedded partner phospho-DIP synthase (P-DIPS), has now been obtained. The structure shows a conserved motif of sugar nucleotide transferases (COG1213) with a structurally reinforced C-terminal Cys bonded to the core of the protein. A bound arsenosugar identifies the location of the active site for inositol 1-phosphate. Based on homologous structures from several species and the identification of the crucial conserved aspartate residue, a catalytic mechanism for this enzyme is proposed as well as a mode for its association with P-DIPS. This structure imposes constraints on the mode of association, communication and temperature activation of two separate enzymes in T. maritima. For the first time, a working model for the membrane-bound P-DIPS unit has been constructed. This sheds light on the functioning of the phosphatidylserine and phosphatidylinositol synthases involved in many physiological processes that are homologous to P-DIPS. This work provides fresh insights into the synthesis of the unusual thermoprotective compound DIP in hyperthermophiles.