The ORCs are Coming! Image of the Week - May 15, 2017
CIL:40985 - http://www.cellimagelibrary.org/images/40985
Description: Model of the yeast Origin Recognition Complex (ORC) complexed with double stranded DNA incorporating a sequence that encodes the replication origin. The 3D structure of the complex with bound DNA was determined by single particle cryo-electron microscopy, and the surface envelope is shown here in grey. The locations of the ORC subunits are shown and superimposed molecular structures in yellow are models of the ORC AAA+ subunits (determined by x-ray crystallography for the related archaeal protein). The ORC is a six-protein machine with a slightly twisted half-ring conformation that is proposed to wrap around and bend approximately 70 base pairs of double stranded DNA (red and blue). When a replication initiator Cdc6 (green) joins ORC, the partial ring is now complete and ready to load another protein onto the DNA. The DNA is modeled into the determined ORC-Cdc6 protein structure. This last protein (not shown) is the enzyme that unwinds the double stranded DNA so each strand can be replicated.
Authors: Bruce Stillman, Huilin Li, and Jingchuan Sun
Licensing: Public Domain: This image is in the public domain and thus free of any copyright restrictions. However, as is the norm in scientific publishing and as a matter of courtesy, any user should credit the content provider for any public or private use of this image whenever possible.
