6qib

Publication Abstract from PubMed

DNA polymerase (Pol ), the major leading-strand DNA polymerase in eukaryotes, has a catalytic subunit (Pol2) and three non-catalytic subunits. The N-terminal half of Pol2 (Pol2CORE) exhibits both polymerase and exonuclease activity. It has been suggested that both the non-catalytic C-terminal domain of Pol2 (with the two cysteine motifs CysA and CysB) and Pol2CORE (with the CysX cysteine motif) are likely to coordinate an Fe-S cluster. Here, we present two new crystal structures of Pol2CORE with an Fe-S cluster bound to the CysX motif, supported by an anomalous signal at that position. Furthermore we show that purified four-subunit Pol , Pol CysAMUT (C2111S/C2133S), and Pol CysBMUT (C2167S/C2181S) all have an Fe-S cluster that is not present in Pol CysXMUT (C665S/C668S). Pol CysAMUT and Pol CysBMUT behave similarly to wild-type Pol in in vitro assays, but Pol CysXMUT has severely compromised DNA polymerase activity that is not the result of an excessive exonuclease activity. Tetrad analyses show that haploid yeast strains carrying CysXMUT are inviable. In conclusion, Pol has a single Fe-S cluster bound at the base of the P-domain, and this Fe-S cluster is essential for cell viability and polymerase activity.

Structural evidence for an essential Fe-S cluster in the catalytic core domain of DNA polymerase .,Ter Beek J, Parkash V, Bylund GO, Osterman P, Sauer-Eriksson AE, Johansson E Nucleic Acids Res. 2019 Apr 10. pii: 5436772. doi: 10.1093/nar/gkz248. PMID:30968138^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.