1MIV: Crystal Structure Of Bacillus Stearothermophilus Cca-Adding Enzyme

CCA-adding enzymes polymerize CCA onto the 3' terminus of immature tRNAs without using a nucleic acid template. The 3.0 A resolution crystal structures of the CCA-adding enzyme from Bacillus stearothermophilus and its complexes with ATP or CTP reveal a seahorse-shaped subunit consisting of four domains: head, neck, body, and tail. The head is structurally homologous to the palm domain of DNA polymerase beta but has additional structural features and functions. The neck, body, and tail represent new protein folding motifs. The neck provides a specific template for the incoming ATP or CTP, whereas the body and tail may bind tRNA. Each subunit has one active site capable of switching its base specificity between ATP and CTP, an important component of the CCA-adding mechanism.
PDB ID: 1MIVDownload
MMDB ID: 21469
PDB Deposition Date: 2002/8/23
Updated in MMDB: 2007/11
Experimental Method:
x-ray diffraction
Resolution: 3.5  Å
Source Organism:
Similar Structures:
Biological Unit for 1MIV: dimeric; determined by author
Molecular Components in 1MIV
Label Count Molecule
Proteins (2 molecules)
tRNA Cca-adding Enzyme
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB