PDBsum entry: 1wlj

Hydrolase

PDB id: 1wlj

Contents

Protein chain

168 a.a. *

Ligands

ACT

U5P

Metals

_MN ×3

Waters ×79

* Residue conservation analysis

PDB id:

1wlj

Name:

Hydrolase

Title:

Human isg20

Structure:

Interferon stimulated gene 20kda. Chain: a. Synonym: interferon stimulated gene product of 20kda, interferon stimulated gene (20kd). Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.90Å R-factor: 0.207 R-free: 0.227

Authors:

T.Horio,M.Murai,T.Inoue,T.Hamasaki,T.Tanaka,T.Ohgi

Key ref:

T.Horio et al. (2004). Crystal structure of human ISG20, an interferon-induced antiviral ribonuclease. FEBS Lett, 577, 111-116. PubMed id: 15527770 DOI: 10.1016/j.febslet.2004.09.074

Date:

28-Jun-04 Release date: 21-Dec-04

Protein chain

Q96AZ6  (ISG20_HUMAN) -  Interferon-stimulated gene 20 kDa protein

Seq: 181 a.a.

Struc: 168 a.a.

Enzyme reactions

• Enzyme class: E.C.3.1.13.1 - Exoribonuclease Ii.
• Reaction: Exonucleolytic cleavage in the 3'- to 5'-direction to yield nucleoside 5'-phosphates.

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (4 terms)
• Biological process: cell proliferation (4 terms)
• Biochemical function: nucleic acid binding (9 terms)

DOI no: 10.1016/j.febslet.2004.09.074

FEBS Lett 577:111-116 (2004)

PubMed id: 15527770

Crystal structure of human ISG20, an interferon-induced antiviral ribonuclease.

T.Horio, M.Murai, T.Inoue, T.Hamasaki, T.Tanaka, T.Ohgi.

ABSTRACT

ISG20 is an interferon-induced antiviral exoribonuclease that acts on single-stranded RNA and also has minor activity towards single-stranded DNA. It belongs to the DEDDh group of RNases of the DEDD exonuclease superfamily. We have solved the crystal structure of human ISG20 complexed with two Mn2+ ions and uridine 5'-monophosphate (UMP) at 1.9 A resolution. Its structure, including that of the active site, is very similar to those of the corresponding domains of two DEDDh-group DNases, the epsilon subunit of Escherichia coli DNA polymerase III and E. coli exonuclease I, strongly suggesting that its catalytic mechanism is identical to that of the two DNases. However, ISG20 also has distinctive residues, Met14 and Arg53, to accommodate hydrogen bonds with the 2'-OH group of the UMP ribose, and these residues may be responsible for the preference of ISG20 for RNA substrates.

Selected figure(s)

Figure 2.
Fig. 2. Ribbon diagrams based on the crystal structures of (A) human ISG20, (B) the N-terminal domain of the E. coli DNA polymerase III epsilon subunit ( epsilon 186; PDB code 1J54 [12]), and (C) the N-terminal exonuclease domain of E. coli ExoI (PDB code 1FXX [13]). In (A) and (B), nucleotides and Mn^2+ ions bound at the active sites are shown in stick and sphere representations, respectively. The sphere in (C) represents a Mg^2+ ion found in the active site of ExoI.

Figure 4.
Fig. 4. Active-site structures of (A) ISG20 and (B) epsilon 186. Small blue spheres represent water molecules. Coordinate bonds between Mn^2+ ions and ligands are shown as yellow dotted lines and hydrogen bonds as red dotted lines.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: FEBS Lett (2004, 577, 111-116) copyright 2004.

Figures were selected by an automated process.