PDBsum entry 4wc6

Transferase/RNA

PDB id: 4wc6

Contents

Protein chain

367 a.a.

DNA/RNA

Ligands

ATP

PDB id:

4wc6

Name:

Transferase/RNA

Title:

Structure of tRNA-processing enzyme complex 4

Structure:

Poly a polymerase. Chain: a. Fragment: unp residues 443-824. Synonym: a-adding enzyme. Engineered: yes. RNA (75-mer). Chain: b. Engineered: yes

Source:

Aquifex aeolicus. Organism_taxid: 224324. Strain: vf5. Gene: pcnb1, aq_411. Expressed in: escherichia coli. Expression_system_taxid: 562. Synthetic: yes. Thermotoga maritima msb8. Organism_taxid: 243274.

Resolution:

3.41Å R-factor: 0.270 R-free: 0.327

Authors:

S.Yamashita,K.Tomita

Key ref:

S.Yamashita et al. (2015). Measurement of Acceptor-TΨC Helix Length of tRNA for Terminal A76-Addition by A-Adding Enzyme. Structure, 23, 830-842. PubMed id: 25914059 DOI: 10.1016/j.str.2015.03.013

Date:

04-Sep-14 Release date: 15-Apr-15

Protein chain

O66728  (O66728_AQUAE) -  A-adding tRNA nucleotidyltransferase from Aquifex aeolicus (strain VF5)

Seq: 824 a.a.

Struc: 367 a.a.*

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

DNA/RNA chain

G-G-C-C-A-G-G-U-A-G-C-U-C-A-G-U-U-G-G-U-A-G-A-G-C-A-C-U-G-G-A-C-U-G-A-A-A-A-U- 75 bases

Enzyme reactions

• Enzyme class: E.C.2.7.7.- - ?????

DOI no: 10.1016/j.str.2015.03.013

Structure 23:830-842 (2015)

PubMed id: 25914059

Measurement of Acceptor-TΨC Helix Length of tRNA for Terminal A76-Addition by A-Adding Enzyme.

S.Yamashita, A.Martinez, K.Tomita.

ABSTRACT

The 3'-terminal CCA (C74C75A76-3') of tRNA is required for protein synthesis. In Aquifex aeolicus, the CCA-3' is synthesized by CC-adding and A-adding enzymes, although in most organisms, CCA is synthesized by a single CCA-adding enzyme. The mechanisms by which the A-adding enzyme adds only A76, but not C74C75, onto tRNA remained elusive. The complex structures of the enzyme with various tRNAs revealed the presence of a single tRNA binding site on the enzyme, with the enzyme measuring the acceptor-TΨC helix length of tRNA. The 3'-C75 of tRNA lacking A76 can reach the active site and the size and shape of the nucleotide binding pocket at the insertion stage are suitable for ATP. The 3'-C74 of tRNA lacking C75A76 cannot reach the active site, although CTP or ATP can bind the active pocket. Thus, the A-adding enzyme adds only A76, but not C74C75, onto tRNA.