PDBsum entry 3h37

Transferase

PDB id: 3h37

Contents

Protein chains

415 a.a. *

Waters ×36

* Residue conservation analysis

PDB id:

3h37

Name:

Transferase

Title:

The structure of cca-adding enzyme apo form i

Structure:

tRNA nucleotidyl transferase-related protein. Chain: a, b. Fragment: unp residues 437-863. Synonym: tRNA nucleotidyltransferase, tRNA adenyl-/cytidyl- transferase, tRNA cca-pyrophosphorylase, tRNA-nt. Engineered: yes

Source:

Thermotoga maritima. Organism_taxid: 2336. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.85Å R-factor: 0.232 R-free: 0.267

Authors:

Y.Toh,K.Tomita

Key ref:

Y.Toh et al. (2009). Mechanism for the definition of elongation and termination by the class II CCA-adding enzyme. Embo J, 28, 3353-3365. PubMed id: 19745807

Date:

16-Apr-09 Release date: 13-Oct-09

Protein chains

Q9WZH4  (Q9WZH4_THEMA) -  tRNA nucleotidyl transferase-related protein from Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8)

Seq: 863 a.a.

Struc: 415 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.2.7.7.25 - Transferred entry: 2.7.7.72.
• Reaction: ATP + tRNA(n) = diphosphate + tRNA(n+1)

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

reference

Embo J 28:3353-3365 (2009)

PubMed id: 19745807

Mechanism for the definition of elongation and termination by the class II CCA-adding enzyme.

Y.Toh, D.Takeshita, T.Numata, S.Fukai, O.Nureki, K.Tomita.

ABSTRACT

The CCA-adding enzyme synthesizes the CCA sequence at the 3' end of tRNA without a nucleic acid template. The crystal structures of class II Thermotoga maritima CCA-adding enzyme and its complexes with CTP or ATP were determined. The structure-based replacement of both the catalytic heads and nucleobase-interacting neck domains of the phylogenetically closely related Aquifex aeolicus A-adding enzyme by the corresponding domains of the T. maritima CCA-adding enzyme allowed the A-adding enzyme to add CCA in vivo and in vitro. However, the replacement of only the catalytic head domain did not allow the A-adding enzyme to add CCA, and the enzyme exhibited (A, C)-adding activity. We identified the region in the neck domain that prevents (A, C)-adding activity and defines the number of nucleotide incorporations and the specificity for correct CCA addition. We also identified the region in the head domain that defines the terminal A addition after CC addition. The results collectively suggest that, in the class II CCA-adding enzyme, the head and neck domains collaboratively and dynamically define the number of nucleotide additions and the specificity of nucleotide selection.