The ADP-ribosyltransferase PARP10/ARTD10 interacts with proliferating cell nuclear antigen (PCNA) and is required for DNA damage tolerance.

All cells rely on genomic stability mechanisms to protect against DNA alterations. PCNA is a master regulator of DNA replication and S-phase-coupled repair. PCNA post-translational modifications by ubiquitination and SUMOylation dictate how cells stabilize and re-start replication forks stalled at sites of damaged DNA. PCNA mono-ubiquitination recruits low fidelity DNA polymerases to promote error-prone replication across DNA lesions. Here, we identify the mono-ADP-ribosyltransferase PARP10/ARTD10 as a novel PCNA binding partner. PARP10 knockdown results in genomic instability and DNA damage hypersensitivity. Importantly, we show that PARP10 binding to PCNA is required for translesion DNA synthesis. Our work identifies a novel PCNA-linked mechanism for genome protection, centered on post-translational modification by mono-ADP-ribosylation.

Defining a kinetic mechanism for l-DOPA 2,3 dioxygenase, a single-domain type I extradiol dioxygenase from Streptomyces lincolnensis.

l-DOPA-2,3-dioxygenase from Streptomyces lincolnensis is a single domain type I extradiol dioxygenase of the vicinal oxygen chelate superfamily and catalyzes the second step in the metabolism of the propylhygric acid moiety of the antibiotic, lincomycin. In this report, the kinetic mechanism of l-DOPA dioxygenase is interrogated using stopped-flow in order to determine microscopic rate constants. Pre-steady state, progress curve and steady-state data were combined in a global kinetic analysis using KinTek Explorer in order to define and constrain a kinetic model for the type I l-DOPA dioxygenase. The data are best described by a four step mechanism, in which the cyclization of the enzymatic product is not enzyme catalyzed.