Summary information and primary citation
- PDB-id
-
6qx8;
DSSR-derived features in text and
JSON formats; DNAproDB
- Class
- RNA binding protein
- Method
- cryo-EM (4.07 Å)
- Summary
- Influenza a virus (a-nt-60-1968) polymerase dimer of
heterotrimer in complex with 5' crna promoter
- Reference
-
Fan H, Walker AP, Carrique L, Keown JR, Serna Martin I,
Karia D, Sharps J, Hengrung N, Pardon E, Steyaert J,
Grimes JM, Fodor E (2019): "Structures
of influenza A virus RNA polymerase offer insight into
viral genome replication." Nature,
573, 287-290. doi: 10.1038/s41586-019-1530-7.
- Abstract
- Influenza A viruses are responsible for seasonal
epidemics, and pandemics can arise from the transmission of
novel zoonotic influenza A viruses to
humans<sub>1,2</sub>. Influenza A viruses
contain a segmented negative-sense RNA genome, which is
transcribed and replicated by the viral-RNA-dependent RNA
polymerase (FluPol<sub>A</sub>) composed of
PB1, PB2 and PA subunits<sub>3-5</sub>.
Although the high-resolution crystal structure of
FluPol<sub>A</sub> of bat influenza A
virus has previously been reported<sub>6</sub>,
there are no complete structures available for human and
avian FluPol<sub>A</sub>. Furthermore, the
molecular mechanisms of genomic viral RNA (vRNA)
replication-which proceeds through a complementary RNA
(cRNA) replicative intermediate, and requires
oligomerization of the
polymerase<sub>7-10</sub>-remain largely
unknown. Here, using crystallography and cryo-electron
microscopy, we determine the structures of
FluPol<sub>A</sub> from human
influenza A/NT/60/1968 (H3N2) and avian
influenza A/duck/Fujian/01/2002 (H5N1) viruses at a
resolution of 3.0-4.3 Å, in the presence or absence of
a cRNA or vRNA template. In solution,
FluPol<sub>A</sub> forms dimers of
heterotrimers through the C-terminal domain of the PA
subunit, the thumb subdomain of PB1 and the N1 subdomain of
PB2. The cryo-electron microscopy structure of monomeric
FluPol<sub>A</sub> bound to the cRNA
template reveals a binding site for the 3' cRNA at the
dimer interface. We use a combination of cell-based and in
vitro assays to show that the interface of the
FluPol<sub>A</sub> dimer is required for vRNA
synthesis during replication of the viral genome. We also
show that a nanobody (a single-domain antibody) that
interferes with FluPol<sub>A</sub> dimerization
inhibits the synthesis of vRNA and, consequently, inhibits
virus replication in infected cells. Our study provides
high-resolution structures of medically relevant
FluPol<sub>A</sub>, as well as insights into
the replication mechanisms of the viral RNA genome. In
addition, our work identifies sites in
FluPol<sub>A</sub> that could be targeted in
the development of antiviral drugs.
