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Welcome to BIOISIS ... the resource for macromolecular SAXS.
Experiment of the Month
Modeling of SAM-1 Riboswitch (apo state)
Low_res_thumbnail SAM-1 riboswitch binds a small metabolite (SAM). Crystal structures of bound and unbound states demonstrate nearly identical structures unlike the solution state where SAXS data showed two different states of the riboswitch. The riboswitch appears to occupy a single bound state in the presence of SAM identical to the crystal structure whereas in the absence of SAM, the riboswitch appears to occupy many conformational states. Based on the X-ray crystal structure, SAXS data in the absence of SAM-1 was used as a modeling constraint in torsion angle molecular dynamic simulations. Results demonstrate a scissoring of the riboswitch for opening the metabolite binding site.
    

Recent Posts

IMPACT OF MACROMOLECULAR CROWDING ON DNA REPLICATION | Link  

Novel application of SAXS using changes in the radius-of-gyration as a function of crowding agent to follow the compaction of an enzyme (in this case the large DNA replication machinery). These types of SAXS studies can be applied to other systems and highlight the effects of modulating water activity on macromolecular structure.
KRATKY PRIZE SAS2012 | Link  

Otto Kratky prize was awarded to Ilja Voets
SAXS WITH MEMBRANE PROTEINS AT SAS2012 | Link  

Javier Perez presented an awesome lecture on SAXS with membrane proteins using the SOLIEL beamline. They use a SAXS instrument with a coupled size-exclusion chromatography system, UV absorbance and refractive index. The get nearly ideal buffer subtraction correcting for free detergent and detergent vesicles. Their approach determines very reliably the number of detergents per protein using two separate instrumentation approaches that was further validated computationally with molecular dynamics.
GUINIER PRIZE AND SAS2016 | Link  

Guinier Prize was presented to Otto Glatter for lifetime contributions to SAS with special mention of the IFT and his seminal book with O. Kratky. SAS2015 will be in Berlin and SAS2018 will be in Michigan.