6EXT

Crystal structure of the DNA binding domain of fission yeast Sap1

Summary for 6EXT

• Entry DOI: 10.2210/pdb6ext/pdb
• Descriptor: Switch-activating protein 1 (2 entities in total)
• Functional Keywords: s. pombe, mating type switch, dna replication, myb domain, dna binding protein
• Biological source: Schizosaccharomyces pombe (strain 972 / ATCC 24843) (Fission yeast)
• Total number of polymer chains: 1
• Total formula weight: 13832.32

Authors

Ekundayo, B.,Joergensen, M.,Schalch, T. (deposition date: 2017-11-09, release date: 2018-11-28, Last modification date: 2024-10-23)

Primary citation

Jorgensen, M.M.,Ekundayo, B.,Zaratiegui, M.,Skriver, K.,Thon, G.,Schalch, T.
Structure of the replication regulator Sap1 reveals functionally important interfaces.
Sci Rep, 8:10930-10930, 2018

PubMed Abstract: The mechanism by which specific protein-DNA complexes induce programmed replication fork stalling in the eukaryotic genome remains poorly understood. In order to shed light on this process we carried out structural investigations on the essential fission yeast protein Sap1. Sap1 was identified as a protein involved in mating-type switching in Schizosaccharomyces pombe, and has been shown to be involved in programmed replication fork stalling. Interestingly, Sap1 assumes two different DNA binding modes. At the mating-type locus dimers of Sap1 bind the SAS1 sequence in a head-to-head arrangement, while they bind to replication fork blocking sites at rDNA and Tf2 transposons in a head-to-tail mode. In this study, we have solved the crystal structure of the Sap1 DNA binding domain and we observe that Sap1 molecules interact in the crystal using a head-to-tail arrangement that is compatible with DNA binding. We find that Sap1 mutations which alleviate replication-fork blockage at Tf2 transposons in CENP-B mutants map to the head-to-tail interface. Furthermore, several other mutations introduced in this interface are found to be lethal. Our data suggests that essential functions of Sap1 depend on its head-to-tail oligomerization.

PubMed: 30026545
DOI: 10.1038/s41598-018-29198-9

Experimental method

X-RAY DIFFRACTION (1.5 Å)