Summary information and primary citation
- PDB-id
-
7mpn;
DSSR-derived features in text and
JSON formats; DNAproDB
- Class
- RNA binding protein-RNA
- Method
- X-ray (1.94 Å)
- Summary
- Bartonella henselae nrnc bound to pgc
- Reference
-
Lormand JD, Kim SK, Walters-Marrah GA, Brownfield BA,
Fromme JC, Winkler WC, Goodson JR, Lee VT, Sondermann H
(2021): "Structural
characterization of NrnC identifies unifying features of
dinucleotidases." Elife,
10. doi: 10.7554/eLife.70146.
- Abstract
- RNA degradation is fundamental for cellular
homeostasis. The process is carried out by various classes
of endolytic and exolytic enzymes that together degrade an
RNA polymer to mono-ribonucleotides. Within the
exoribonucleases, nano-RNases play a unique role as they
act on the smallest breakdown products and hence catalyze
the final steps in the process. We recently showed that
oligoribonuclease (Orn) acts as a dedicated
diribonucleotidase, defining the ultimate step in RNA
degradation that is crucial for cellular fitness (Kim et
al., 2019). Whether such a specific activity exists in
organisms that lack Orn-type exoribonucleases remained
unclear. Through quantitative structure-function analyses,
we show here that NrnC-type RNases share this narrow
substrate length preference with Orn. Although NrnC and Orn
employ similar structural features that distinguish these
two classes of dinucleotidases from other exonucleases, the
key determinants for dinucleotidase activity are realized
through distinct structural scaffolds. The structures,
together with comparative genomic analyses of the phylogeny
of DEDD-type exoribonucleases, indicate convergent
evolution as the mechanism of how dinucleotidase activity
emerged repeatedly in various organisms. The evolutionary
pressure to maintain dinucleotidase activity further
underlines the important role these analogous proteins play
for cell growth.
