5b7j | pdb_00005b7j
Structure model of Sap1-DNA complex
Structural highlights
FunctionSAP1_SCHPO Binds to sequences required for mating-type switching. Makes a simultaneous contact with both the alpha and beta domains of the switch-activating site SAS1. Also binds to replication fork barrier 1 (RFB1) located within a 78 base pair sequence near the 3' end of the rRNA coding region. This leads to replication fork blockage. It binds the consensus sequence 5'-TA[AG]GCAGNTN[CT]AACG[AC]G-3'. Has a role in chromosome organization and integrity where it is involved in chromosome segregation. Has a role in sister chromatid cohesion and condensation. Publication Abstract from PubMedA central step in the initiation of chromosomal DNA replication in eukaryotes is the assembly of pre-replicative complex (pre-RC) at late M and early G1 phase of the cell cycles. Since 1973, four proteins or protein complexes, including cell division control protein 6 (Cdc6)/Cdc18, minichromosome maintenance protein complex, origin recognition complex (ORC), and Cdt1, are known components of the pre-RC. Previously, we reported that a non-ORC protein binds to the essential element Delta9 of the Schizosaccharomyces pombe DNA-replication origin ARS3001. In this study, we identified that the non-ORC protein is Sap1. Like ORC, Sap1 binds to DNA origins during cell growth cycles. But unlike ORC, which binds to asymmetric AT-rich sequences through its nine AT-hook motifs, Sap1 preferentially binds to a DNA sequence of 5'-(A/T) n (C/G)(A/T)9-10(G/C)(A/T) n -3' (n >/= 1). We also found that Sap1 and ORC physically interact. We further demonstrated that Sap1 is required for the assembly of the pre-RC because of its essential role in recruiting Cdc18 to DNA origins. Thus, we conclude that Sap1 is a replication-initiation factor that directly participates in the assembly of the pre-RC. DNA-replication origins in fission yeast are defined by possessing two essential elements with one bound by ORC and the other by Sap1. Sap1 is a replication-initiation factor essential for the assembly of pre-replicative complex in the fission yeast Schizosaccharomyces pombe.,Guan L, He P, Yang F, Zhang Y, Hu Y, Ding J, Hua Y, Zhang Y, Ye Q, Hu J, Wang T, Jin C, Kong D J Biol Chem. 2017 Apr 14;292(15):6056-6075. doi: 10.1074/jbc.M116.767806. Epub, 2017 Feb 21. PMID:28223353[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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