PDBsum entry 2g2n

Unknown function

PDB id: 2g2n

Contents

Protein chains

111 a.a. *

Ligands

SO4 ×2

Metals

_ZN ×18

Waters ×271

* Residue conservation analysis

PDB id:

2g2n

Name:

Unknown function

Title:

Crystal structure of e.Coli transthyretin-related protein with bound zn

Structure:

Transthyretin-like protein. Chain: a, b, c, d. Synonym: transthyretin-related protein. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Tetramer (from PQS)

Resolution:

1.65Å R-factor: 0.200 R-free: 0.234

Authors:

E.Lundberg,S.Backstrom,U.H.Sauer,A.E.Sauer-Eriksson

Key ref:

E.Lundberg et al. (2006). The transthyretin-related protein: structural investigation of a novel protein family. J Struct Biol, 155, 445-457. PubMed id: 16723258

Date:

16-Feb-06 Release date: 12-Dec-06

Protein chains

P76341  (HIUH_ECOLI) -  5-hydroxyisourate hydrolase from Escherichia coli (strain K12)

Seq: 137 a.a.

Struc: 111 a.a.

Enzyme reactions

• Enzyme class: E.C.3.5.2.17 - hydroxyisourate hydrolase.
• Pathway: AMP Catabolism
• Reaction: 5-hydroxyisourate + H2O = 5-hydroxy-2-oxo-4-ureido-2,5-dihydro- 1H-imidazole-5-carboxylate + H⁺

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

Key reference

J Struct Biol 155:445-457 (2006)

PubMed id: 16723258

The transthyretin-related protein: structural investigation of a novel protein family.

E.Lundberg, S.Bäckström, U.H.Sauer, A.E.Sauer-Eriksson.

ABSTRACT

The transthyretin-related protein (TRP) family comprises proteins predicted to be structurally related to the homotetrameric transport protein transthyretin (TTR). The function of TRPs is not yet fully established, but recent data suggest that they are involved in purine catabolism. We have determined the three-dimensional structure of the Escherichia coli TRP in two crystal forms; one at 1.65 A resolution in the presence of zinc, and the other at 2.1 A resolution in the presence of zinc and bromide. The structures revealed five zinc-ion-binding sites per monomer. Of these, the zinc ions bound at sites I and II are coordinated in tetrahedral geometries to the side chains of residues His9, His96, His98, Ser114, and three water molecules at the putative ligand-binding site. Of these four residues, His9, His98, and Ser114 are conserved. His9 and His98 bind the central zinc (site I) together with two water molecules. The side chain of His98 also binds to the zinc ion at site II. Bromide ions bind at site I only, replacing one of the water molecules coordinated to the zinc ion. The C-terminal four amino acid sequence motif Y-[RK]-G-[ST] constitutes the signature sequence of the TRP family. Two Tyr111 residues form direct hydrogen bonds to each other over the tetramer interface at the area, which in TTR constitutes the rear part of its thyroxine-binding channel. The putative substrate/ligand-binding channel of TRP is consequently shallower and broader than its counterpart in TTR.