4fz2

Crystal structure of the fourth type of archaeal tRNA splicing endonuclease from Candidatus Micrarchaeum acidiphilum ARMAN-2

spinqualitylabelsall models 4fz2, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fz2 is a 2 chain structure with sequence from Candidatus Micrarchaeum acidiphilum ARMAN-2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function C7DIA5_MICA2 Publication Abstract from PubMed Cleavage of introns from precursor transfer RNAs (tRNAs) by tRNA splicing endonuclease (EndA) is essential for tRNA maturation in Archaea and Eukarya. In the past, archaeal EndAs were classified into three types (alpha'2, alpha4 and alpha2beta2) according to subunit composition. Recently, we have identified a fourth type of archaeal EndA from an uncultivated archaeon Candidatus Micrarchaeum acidiphilum, referred to as ARMAN-2, which is deeply branched within Euryarchaea. The ARMAN-2 EndA forms an epsilon2 homodimer and has broad substrate specificity like the alpha2beta2 type EndAs found in Crenarchaea and Nanoarchaea. However, the precise architecture of ARMAN-2 EndA was unknown. Here, we report the crystal structure of the epsilon2 homodimer of ARMAN-2 EndA. The structure reveals that the epsilon protomer is separated into three novel units (alphaN, alpha and betaC) fused by two distinct linkers, although the overall structure of ARMAN-2 EndA is similar to those of the other three types of archaeal EndAs. Structural comparison and mutational analyses reveal that an ARMAN-2 type-specific loop (ASL) is involved in the broad substrate specificity and that K161 in the ASL functions as the RNA recognition site. These findings suggest that the broad substrate specificities of epsilon2 and alpha2beta2 EndAs were separately acquired through different evolutionary processes. X-ray structure of the fourth type of archaeal tRNA splicing endonuclease: insights into the evolution of a novel three-unit composition and a unique loop involved in broad substrate specificity.,Hirata A, Fujishima K, Yamagami R, Kawamura T, Banfield JF, Kanai A, Hori H Nucleic Acids Res. 2012 Nov 1;40(20):10554-66. doi: 10.1093/nar/gks826. Epub 2012, Aug 31. PMID:22941657 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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