Category: Science Highlights

Characterizing flexible macromolecules with SAXS.

Unstructured proteins, RNA or DNA components provide functionally important flexibility that is key to many macromolecular assemblies throughout cell biology. As objective, quantitative experimental measures of flexibility and disorder in solution are limited, small angle scattering (SAS), and in particular small angle X-ray scattering (SAXS), provides a critical technology to assess macromolecular flexibility as well…
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Bend, Fray, Cut: A Unified Mechanism for Exo- and Endo-Nucleases

Two related manuscripts appear in the April 15 issue of CELL reporting results endo and exo nucleases important for DNA repair. Both groups of researchers made extensive use of the MX capabilities of the SIBYLS beamline to collect critical crystallographic data. The crystal structures of human flap endonuclease (FEN1) in complex with both substrate and…
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The ABC of DNA repair

Rad50 is an ABC-type ATPase that forms a complex with the nuclease Mre11 and plays an essential role in the signaling and repair of DNA damage. Now crystal structures and SAXS analyses determined here at the SIBYLS beamline, along with functional assays, reveal how Rad50 transmits information between the ATPase and Mre11-binding sites, and the…
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Nitric Oxide Synthase is the PDB Molecule of the Month

One of our favorite molecules has been selected as the January [Molecule of the Month]( by the RCSB Protein Data Bank.

Fast X-ray Scattering : FoXS

SIBYLS staff together with Dina Schneidman from Andrej Sali’s lab have developed the FoXS web application. FoXS (Fast X-Ray Scattering) is a rapid method for computing a SAXS profile of a given structure and for matching of the computed and experimental profiles. In our recent publication in Nucleic Acid Research we describe the interface and…
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Mre11 is the May 2010 PSI featured molecule

Near and dear to our heart, Mre11, has been chosen as the May 2010 [featured molecule]( by the Protein Structure Initiative. Additionally, the blurb on the PSI website features a beautiful rendering of the *Pyrococcus furiosus* and *Thermotoga maritima* Mre11 nucleases created by [David Goodsell](

Rotary motion of Rho hexameric helicase elucidated

UC Berkeley researchers, James Berger and Nathan Thomsen, used the SIBYLS beamline to solve the structure of a hexameric helicase, the Rho transcription termination factor (from E. coli), bound to both ATP mimics and an RNA substrate. The results showed that Rho functions like a rotary engine: as the motor spins, it pulls RNA strands…
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Science selects ABA receptors as breakthrough of the year runner-up

Science magazine has selected plant [ABA receptors]( as one of the runners-up for the 2009 Breakthrough of the Year award. MX and SAXS data collected at the SIBYLS beamline were integral to the research article published in the Dec 4th issue of Science. This work was recognized as contributing to the fundamental breakthrough in the…
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