2zh2

From Proteopedia

Complex structure of AFCCA with tRNAminiDAC

PDB ID 2zh2

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Structural highlights

2zh2 is a 2 chain structure with sequence from Archaeoglobus fulgidus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.66Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CCA_ARCFU Catalyzes the addition and repair of the essential 3'-terminal CCA sequence in tRNAs without using a nucleic acid template. Adds these three nucleotides in the order of C, C, and A to the tRNA nucleotide-73, using CTP and ATP as substrates and producing inorganic pyrophosphate.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

CCA-adding enzyme builds the 3'-end CCA of tRNA without a nucleic acid template. The mechanism for the maintenance of fidelity during the CCA-adding reaction remains elusive. Here, we present almost a dozen complex structures of the class I CCA-adding enzyme and tRNA mini-helices (mini-D(73)N(74), mini-D(73)N(74)C(75) and mini-D(73)C(74)N(75); D(73) is a discriminator nucleotide and N is either A, G, or U). The mini-D(73)N(74) complexes adopt catalytically inactive open forms, and CTP shifts the enzymes to the active closed forms and allows N(74) to flip for CMP incorporation. In contrast, unlike the catalytically active closed form of the mini-D(73)C(74)C(75) complex, the mini-D(73)N(74)C(75) and mini-D(73)C(74)N(75) complexes adopt inactive open forms. Only the mini-D(73)C(74)U(75) accepts AMP to a similar extent as mini-D(73)C(74)C(75), and ATP shifts the enzyme to a closed, active form and allows U(75) to flip for AMP incorporation. These findings suggest that the 3'-region of RNA is proofread, after two nucleotide additions, in the closed, active form of the complex at the AMP incorporation stage. This proofreading is a prerequisite for the maintenance of fidelity for complete CCA synthesis.

Molecular basis for maintenance of fidelity during the CCA-adding reaction by a CCA-adding enzyme.,Toh Y, Numata T, Watanabe K, Takeshita D, Nureki O, Tomita K EMBO J. 2008 Jul 23;27(14):1944-52. Epub 2008 Jun 26. PMID:18583961^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Okabe M, Tomita K, Ishitani R, Ishii R, Takeuchi N, Arisaka F, Nureki O, Yokoyama S. Divergent evolutions of trinucleotide polymerization revealed by an archaeal CCA-adding enzyme structure. EMBO J. 2003 Nov 3;22(21):5918-27. PMID:14592988 doi:http://dx.doi.org/10.1093/emboj/cdg563
↑ Toh Y, Numata T, Watanabe K, Takeshita D, Nureki O, Tomita K. Molecular basis for maintenance of fidelity during the CCA-adding reaction by a CCA-adding enzyme. EMBO J. 2008 Jul 23;27(14):1944-52. Epub 2008 Jun 26. PMID:18583961 doi:10.1038/emboj.2008.124