4kb1

From Proteopedia

Crystal structure of RNase T in complex with a bluge DNA (two nucleotide insertion CT )

PDB ID 4kb1

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Structural highlights

4kb1 is a 4 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.8Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RNT_ECOLI Responsible for the end-turnover of tRNA: specifically removes the terminal AMP residue from uncharged tRNA (tRNA-C-C-A). Also appears to be involved in tRNA biosynthesis, especially in strains lacking other exoribonucleases.[HAMAP-Rule:MF_00157]

Publication Abstract from PubMed

DNA repair mechanisms are essential for preservation of genome integrity. However, it is not clear how DNA are selected and processed at broken ends by exonucleases during repair pathways. Here we show that the DnaQ-like exonuclease RNase T is critical for Escherichia coli resistance to various DNA-damaging agents and UV radiation. RNase T specifically trims the 3' end of structured DNA, including bulge, bubble, and Y-structured DNA, and it can work with Endonuclease V to restore the deaminated base in an inosine-containing heteroduplex DNA. Crystal structure analyses further reveal how RNase T recognizes the bulge DNA by inserting a phenylalanine into the bulge, and as a result the 3' end of blunt-end bulge DNA can be digested by RNase T. In contrast, the homodimeric RNase T interacts with the Y-structured DNA by a different binding mode via a single protomer so that the 3' overhang of the Y-structured DNA can be trimmed closely to the duplex region. Our data suggest that RNase T likely processes bulge and bubble DNA in the Endonuclease V-dependent DNA repair, whereas it processes Y-structured DNA in UV-induced and various other DNA repair pathways. This study thus provides mechanistic insights for RNase T and thousands of DnaQ-like exonucleases in DNA 3'-end processing.

Structural insights into DNA repair by RNase T--an exonuclease processing 3' end of structured DNA in repair pathways.,Hsiao YY, Fang WH, Lee CC, Chen YP, Yuan HS PLoS Biol. 2014 Mar 4;12(3):e1001803. doi: 10.1371/journal.pbio.1001803., eCollection 2014 Mar. PMID:24594808^[1]

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

References

↑ Hsiao YY, Fang WH, Lee CC, Chen YP, Yuan HS. Structural insights into DNA repair by RNase T--an exonuclease processing 3' end of structured DNA in repair pathways. PLoS Biol. 2014 Mar 4;12(3):e1001803. doi: 10.1371/journal.pbio.1001803., eCollection 2014 Mar. PMID:24594808 doi:http://dx.doi.org/10.1371/journal.pbio.1001803