3PQV: Cyclase Homolog

Rcl1 is an essential nucleolar protein required for U3 snoRNA-guided pre-rRNA processing at sites flanking the 18S rRNA sequence. A potential catalytic role for Rcl1 during pre-rRNA cleavage has been suggested based on its primary structure similarity to RNA 3'-terminal phosphate cyclase (Rtc) enzymes, which perform nucleotidyl transfer and phosphoryl transfer reactions at RNA ends. Here, we report the 2.6 A crystal structure of a biologically active yeast Rcl1, which illuminates its modular 4-domain architecture and overall homology with RNA cyclases while revealing numerous local differences that account for why Rtcs possess metal-dependent adenylyltransferase activity and Rcls do not. A conserved oxyanion-binding site in Rcl1 was highlighted for possible catalytic or RNA-binding functions. However, the benign effects of mutations in and around the anion site on Rcl1 activity in vivo militate against such a role.
PDB ID: 3PQVDownload
MMDB ID: 89866
PDB Deposition Date: 2010/11/27
Updated in MMDB: 2011/05
Experimental Method:
x-ray diffraction
Resolution: 2.61  Å
Source Organism:
Similar Structures:
Biological Unit for 3PQV: monomeric; determined by author
Molecular Components in 3PQV
Label Count Molecule
Protein (1 molecule)
Rcl1 Protein
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB