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Crystal structure of the N-terminal BAH domain of Orc1pCrystal structure of the N-terminal BAH domain of Orc1p
Structural highlights
Function[ORC1_YEAST] Component of the origin recognition complex (ORC) that binds origins of replication. It has a role in both chromosomal replication and mating type transcriptional silencing. Binds to the ARS consensus sequence (ACS) of origins of replication.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe N-terminal domain of the largest subunit of the Saccharomyces cerevisiae origin recognition complex (Orc1p) functions in transcriptional silencing and contains a bromo-adjacent homology (BAH) domain found in some chromatin-associated proteins including Sir3p. The 2.2 A crystal structure of the N-terminal domain of Orc1p revealed a BAH core and a non-conserved helical sub-domain. Mutational analyses demonstrated that the helical sub-domain was necessary and sufficient to bind Sir1p, and critical for targeting Sir1p primarily to the cis-acting E silencers at the HMR and HML silent chromatin domains. In the absence of the BAH domain, approximately 14-20% of cells in a population were silenced at the HML locus. Moreover, the distributions of the Sir2p, Sir3p and Sir4p proteins, while normal, were at levels lower than found in wild-type cells. Thus, in the absence of the Orc1p BAH domain, HML resembled silencing of genes adjacent to telomeres. These data are consistent with the view that the Orc1p-Sir1p interaction at the E silencers ensures stable inheritance of pre-established Sir2p, Sir3p and Sir4p complexes at the silent mating type loci. Structure and function of the BAH-containing domain of Orc1p in epigenetic silencing.,Zhang Z, Hayashi MK, Merkel O, Stillman B, Xu RM EMBO J. 2002 Sep 2;21(17):4600-11. PMID:12198162[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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