Summary information and primary citation
- PDB-id
-
7nv1;
DSSR-derived features in text and
JSON formats
- Class
- replication
- Method
- cryo-EM (6.4 Å)
- Summary
- Human pol kappa holoenzyme with ub-pcna
- Reference
-
Lancey C, Tehseen M, Bakshi S, Percival M, Takahashi M,
Sobhy MA, Raducanu VS, Blair K, Muskett FW, Ragan TJ,
Crehuet R, Hamdan SM, De Biasio A (2021): "Cryo-EM
structure of human Pol kappa bound to DNA and
mono-ubiquitylated PCNA." Nat Commun,
12, 6095. doi: 10.1038/s41467-021-26251-6.
- Abstract
- Y-family DNA polymerase κ (Pol κ) can replicate damaged
DNA templates to rescue stalled replication forks. Access
of Pol κ to DNA damage sites is facilitated by its
interaction with the processivity clamp PCNA and is
regulated by PCNA mono-ubiquitylation. Here, we present
cryo-EM reconstructions of human Pol κ bound to DNA, an
incoming nucleotide, and wild type or mono-ubiquitylated
PCNA (Ub-PCNA). In both reconstructions, the internal
PIP-box adjacent to the Pol κ Polymerase-Associated Domain
(PAD) docks the catalytic core to one PCNA protomer in an
angled orientation, bending the DNA exiting the Pol κ
active site through PCNA, while Pol κ C-terminal domain
containing two Ubiquitin Binding Zinc Fingers (UBZs) is
invisible, in agreement with disorder predictions. The
ubiquitin moieties are partly flexible and extend radially
away from PCNA, with the ubiquitin at the Pol κ-bound
protomer appearing more rigid. Activity assays suggest
that, when the internal PIP-box interaction is lost, Pol κ
is retained on DNA by a secondary interaction between the
UBZs and the ubiquitins flexibly conjugated to PCNA. Our
data provide a structural basis for the recruitment of a
Y-family TLS polymerase to sites of DNA damage.
