7M0A

Incomplete in crystallo incorporation by DNA Polymerase Lambda bound to blunt-ended DSB substrate and incoming dTTP

Summary for 7M0A

• Entry DOI: 10.2210/pdb7m0a/pdb
• Descriptor: DNA polymerase lambda, SODIUM ION, CHLORIDE ION, ... (13 entities in total)
• Functional Keywords: nonhomologous end-joining, base excision repair, transferase
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 5
• Total formula weight: 46186.68

Authors

Kaminski, A.M.,Bebenek, K.,Pedersen, L.C.,Kunkel, T.A. (deposition date: 2021-03-10, release date: 2022-03-16, Last modification date: 2023-10-25)

Primary citation

Kaminski, A.M.,Chiruvella, K.K.,Ramsden, D.A.,Bebenek, K.,Kunkel, T.A.,Pedersen, L.C.
Analysis of diverse double-strand break synapsis with Pol lambda reveals basis for unique substrate specificity in nonhomologous end-joining.
Nat Commun, 13:3806-3806, 2022

PubMed Abstract: DNA double-strand breaks (DSBs) threaten genomic stability, since their persistence can lead to loss of critical genetic information, chromosomal translocations or rearrangements, and cell death. DSBs can be repaired through the nonhomologous end-joining pathway (NHEJ), which processes and ligates DNA ends efficiently to prevent or minimize sequence loss. Polymerase λ (Polλ), one of the Family X polymerases, fills sequence gaps of DSB substrates with a strict specificity for a base-paired primer terminus. There is little information regarding Polλ's approach to engaging such substrates. We used in vitro polymerization and cell-based NHEJ assays to explore the contributions of conserved loop regions toward DSB substrate specificity and utilization. In addition, we present multiple crystal structures of Polλ in synapsis with varying biologically relevant DSB end configurations, revealing how key structural features and hydrogen bonding networks work in concert to stabilize these tenuous, potentially cytotoxic DNA lesions during NHEJ.

PubMed: 35778389
DOI: 10.1038/s41467-022-31278-4

Experimental method

X-RAY DIFFRACTION (1.83 Å)