PMID: 32878989

Authors:

Rodriguez AA, Wojtaszek JL, Greer BH, Haldar T, Gates KS, Williams RS, Eichman BF

Title:

An autoinhibitory role for the GRF zinc finger domain of DNA glycosylase NEIL3.

Journal:

J Biol Chem. 2020 Sep 2. pii: RA120.015541. doi: 10.1074/jbc.RA120.015541.

Abstract:

The NEIL3 DNA glycosylase maintains genome integrity during replication by excising oxidized bases from single-stranded DNA (ssDNA) and unhooking interstrand cross-links (ICLs) at fork structures. In addition to its N-terminal catalytic glycosylase domain, NEIL3 contains two tandem C-terminal GRF-type zinc fingers that are absent in the other NEIL paralogs. ssDNA binding by the GRF-ZF motifs helps recruit NEIL3 to replication forks converged at an ICL, but the nature of DNA binding and the effect of the GRF-ZF domain on catalysis of base excision and ICL unhooking is unknown. Here, we show that the tandem GRF-ZFs of NEIL3 provide affinity and specificity for DNA that is greater than each individual motif alone. The crystal structure of the GRF domain shows the tandem ZF motifs adopt a flexible head-to-tail configuration well-suited for binding to multiple ssDNA conformations. Functionally, we establish that the NEIL3 GRF domain inhibits glycosylase activity against monoadducts and ICLs. This autoinhibitory activity contrasts GRF-ZF domains of other DNA processing enzymes, which typically use ssDNA binding to enhance catalytic activity, and suggests that the C-terminal region of NEIL3 is involved in both DNA damage recruitment and enzymatic regulation.