1R8B

Crystal Structures of an Archaeal Class I CCA-Adding Enzyme and Its Nucleotide

Summary for 1R8B

• Entry DOI: 10.2210/pdb1r8b/pdb
• Related: 1R89 1R8A 1R8C
• Descriptor: tRNA nucleotidyltransferase, MANGANESE (II) ION, MAGNESIUM ION, ... (7 entities in total)
• Functional Keywords: cca adding enzyme, incoming nucleotide, nucleotidyltransferase, transferase
• Biological source: Archaeoglobus fulgidus
• Total number of polymer chains: 1
• Total formula weight: 52700.43

Authors

Xiong, Y.,Li, F.,Wang, J.,Weiner, A.M.,Steitz, T.A. (deposition date: 2003-10-23, release date: 2003-12-16, Last modification date: 2024-02-14)

Primary citation

Xiong, Y.,Li, F.,Wang, J.,Weiner, A.M.,Steitz, T.A.
Crystal structures of an archaeal class I CCA-adding enzyme and its nucleotide complexes
Mol.Cell, 12:1165-1172, 2003

PubMed Abstract: CCA-adding enzymes catalyze the addition of CCA onto the 3' terminus of immature tRNAs without using a nucleic acid template and have been divided into two classes based on their amino acid sequences. We have determined the crystal structures of a class I CCA-adding enzyme from Archeoglobus fulgidus (AfCCA) and its complexes with ATP, CTP, or UTP. Although it and the class II bacterial Bacillus stearothermophilus CCA enzyme (BstCCA) have similar dimensions and domain architectures (head, neck, body, and tail), only the polymerase domain is structurally homologous. Moreover, the relative orientation of the head domain with respect to the body and tail domains, which appear likely to bind tRNA, differs significantly between the two enzyme classes. Unlike the class II BstCCA, this enzyme binds nucleotides nonspecifically in the absence of bound tRNA. The shape and electrostatic charge distribution of the AfCCA enzyme suggests a model for tRNA binding that accounts for the phosphates that are protected from chemical modification by tRNA binding to AfCCA. The structures of the AfCCA enzyme and the eukaryotic poly(A) polymerase are very similar, implying a close evolutionary relationship between them.

PubMed: 14636575
DOI: 10.1016/S1097-2765(03)00440-4

Experimental method

X-RAY DIFFRACTION (2 Å)