PDBsum entry 2v6e

Hydrolase

PDB id: 2v6e

Contents

Protein chains

532 a.a.

DNA/RNA

Ligands

VO4 ×2

PDB id:

2v6e

Name:

Hydrolase

Title:

Protelomerase telk complexed with substrate DNA

Structure:

Protelemorase. Chain: a, b. Fragment: c-terminally truncated active resolvase, residues 1-538. Synonym: protelomerase telk538. Engineered: yes. Telrl. Chain: c, e. Engineered: yes. Other_details: target site for telk.

Source:

Klebsiella phage phiko2. Organism_taxid: 255431. Expressed in: escherichia coli. Expression_system_taxid: 511693. Synthetic: yes. Phage n15. Organism_taxid: 40631. Organism_taxid: 40631

Resolution:

3.20Å R-factor: 0.255 R-free: 0.286

Authors:

H.Aihara,W.M.Huang,T.Ellenberger

Key ref:

H.Aihara et al. (2007). An Interlocked Dimer of the Protelomerase TelK Distorts DNA Structure for the Formation of Hairpin Telomeres. Mol Cell, 27, 901-913. PubMed id: 17889664 DOI: 10.1016/j.molcel.2007.07.026

Date:

17-Jul-07 Release date: 02-Oct-07

Protein chains

Q6UAV6  (Q6UAV6_9CAUD) -  Protelomerase from Klebsiella oxytoca phage phiKO2

Seq: 640 a.a.

Struc: 532 a.a.

DNA/RNA chains

C-G-C-G-C-G-T-A-T-A-A-T-G-G-G-C-A-A-T-T-G-T-G-T-G 25 bases

C-A-C-A-C-A-A-T-T-G-C-C-C-A-T-T-A-T-A 19 bases

C-G-C-G-C-G-T-A-T-A-A-T-G-G-G-C-A-A-T-T-G-T-G-T-G 25 bases

C-A-C-A-C-A-A-T-T-G-C-C-C-A-T-T-A-T-A 19 bases

Enzyme reactions

• Enzyme class: E.C.3.1.22.- - ?????

DOI no: 10.1016/j.molcel.2007.07.026

Mol Cell 27:901-913 (2007)

PubMed id: 17889664

An Interlocked Dimer of the Protelomerase TelK Distorts DNA Structure for the Formation of Hairpin Telomeres.

H.Aihara, W.M.Huang, T.Ellenberger.

ABSTRACT

The termini of linear chromosomes are protected by specialized DNA structures known as telomeres that also facilitate the complete replication of DNA ends. The simplest type of telomere is a covalently closed DNA hairpin structure found in linear chromosomes of prokaryotes and viruses. Bidirectional replication of a chromosome with hairpin telomeres produces a catenated circular dimer that is subsequently resolved into unit-length chromosomes by a dedicated DNA cleavage-rejoining enzyme known as a hairpin telomere resolvase (protelomerase). Here we report a crystal structure of the protelomerase TelK from Klebsiella oxytoca phage varphiKO2, in complex with the palindromic target DNA. The structure shows the TelK dimer destabilizes base pairing interactions to promote the refolding of cleaved DNA ends into two hairpin ends. We propose that the hairpinning reaction is made effectively irreversible by a unique protein-induced distortion of the DNA substrate that prevents religation of the cleaved DNA substrate.

Selected figure(s)

Figure 1.
Figure 1. Protelomerase Resolves Replicated Hairpin Telomeres
(A) Replication of a linear chromosome with hairpin telomeres produces a dimeric circular intermediate that is resolved into unit-length chromosomes by the activity of protelomerase.
(B) A model for the hairpin formation reaction by the protelomerase TelK, proposed based on the crystal structure presented in this study.

Figure 6.
Figure 6. DNA Substrate Recognition by TelK
(A) A schematic diagram showing the DNA backbone and base-specific interactions. The protein residues are color coded for each domain according to the scheme in Figure 4C, and DNA backbones are colored to match the structural figures. DNA bases involved in hydrogen-bonding interactions are colored yellow, and those involved in van der Waals contacts are colored cyan. Solid and dashed lines denote electrostatic/hydrogen-bonding and van der Waals interactions, respectively.
(B and C) Base-specific hydrogen-bonding interactions made by the core-binding and catalytic domains (B) and by the C-terminal stirrup domain (C).

The above figures are reprinted from an Open Access publication published by Cell Press: Mol Cell (2007, 27, 901-913) copyright 2007.

Figures were selected by an automated process.