Summary information and primary citation
- PDB-id
-
3va3;
DSSR-derived features in text and
JSON formats
- Class
- hydrolase-DNA
- Method
- X-ray (2.714 Å)
- Summary
- Crystal structure of rnase t in complex with a duplex
DNA product (stem loop DNA with 2 nucleotide 3'
overhang)
- Reference
-
Hsiao Y-Y, Duh Y, Chen YP, Wang YT, Yuan HS (2012):
"How an
exonuclease decides where to stop in trimming of nucleic
acids: crystal structures of RNase T-product
complexes." Nucleic Acids Res.,
40, 8144-8154. doi: 10.1093/nar/gks548.
- Abstract
- Exonucleases are key enzymes in the maintenance of
genome stability, processing of immature RNA precursors and
degradation of unnecessary nucleic acids. However, it
remains unclear how exonucleases digest nucleic acids to
generate correct end products for next-step processing.
Here we show how the exonuclease RNase T stops its trimming
precisely. The crystal structures of RNase T in complex
with a stem-loop DNA, a GG dinucleotide and single-stranded
DNA with different 3'-end sequences demonstrate why a
duplex with a short 3'-overhang, a dinucleotide and a ssDNA
with a 3'-end C cannot be further digested by RNase T.
Several hydrophobic residues in RNase T change their
conformation upon substrate binding and induce an active or
inactive conformation in the active site that construct a
precise machine to determine which substrate should be
digested based on its sequence, length and structure. These
studies thus provide mechanistic insights into how RNase T
prevents over digestion of its various substrates, and the
results can be extrapolated to the thousands of members of
the DEDDh family of exonucleases.
