BioCAT is resuming user operations for the 2025-1 run!
Get Beam time
BioCAT is a national user facility funded by the NIH, and beam time is free for experimenters. Beam time is awarded through the APS GUP process, which considers feasibility and scientific merit.
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Proteins May Prevent Dysfunction and Disease by Relaxing
A new study suggests many proteins remain expanded in the cell, rather than contracting into tight folded shapes.
Learn MoreProteins May Prevent Dysfunction and Disease by Relaxing
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Unearthing the Mechanism of the Frank-Starling Law
Recent X-ray diffraction experiments show that the protein titin is critically important for transmitting the stretch-induced signals within the heart’s muscles known to impact the strength with which the heart contracts. This work not only solves a piece of the mystery of how the frank-Starling law determines cardiac function, but provides an avenue for targeted development of drugs to treat heart failure.
Learn MoreUnearthing the Mechanism of the Frank-Starling Law
Learn MoreScience Highlights
Titin-Based Force Modulates Cardiac Thick and Thin Filaments
The Frank-Starling Law of the Heart states that the heart’s stroke volume increases with greater preload due to increased venous return, allowing the heart to adapt to varying circulatory demands. At the molecular level, increasing preload increases sarcomere length (SL), which alters structures w ithin the sarcomere that are correlated to increased calcium sensitivity upon activation. The titin protein, spanning the half-sarcomere acts as a spring in the I-band, applies a SL-dependent passive force on the myosin containing thick filaments changing its structure and functional properties. Altered titin-based forces play a crucial role in the etiology of many cardiomyopathies; however, the disease state obscures titin’s role, impeding therapeutic solutions. The authors studied titin’s specific role and concluded that reducing titin-based forces blunts structural changes in both thick and thin filaments while leaving the length-dependent OFF-to-ON transition mechanism intact, indicating a clear role for titin in the Frank-Starling mechanism.
How hydrophobicity, side chains, and salt affect the dimensions of disordered proteins
Understanding the driving forces behind stability of denatured state ensembles (DSE’s) and intrinsically disordered proteins (IDP’s) is central to a number of unresolved questions in bimolecular thermodynamics regarding protein folding pathways and foldability, thermodynamic stability, aggregation and misfolding. Researchers at the University of Chicago and Notre Dame used temperature-controlled size-exclusion chromatography-coupled SAXS (SEC-SAXS) and NMR to examine how temperature and solvent ionic strength influences the solution structure(s) of the N-terminal domain of pertactin (PNt). PNt is a valuable model system from a fundamental biophysical point of view, as the full-length 539-residue pertactin folds into a parallel β-helix but the 334 N-terminal residues do not and instead behave as a highly expanded, intrinsically disordered chain.
Myosin-binding protein C regulates the sarcomere lattice and stabilizes the OFF states of myosin heads
Muscle contraction is produced via the interaction of myofilaments and is regulated so that muscle performance matches demand. Myosin-binding protein C (MyBP-C) is a long and flexible protein that is thought to control muscle contraction via the regulation of myosin motors, as mutations lead to debilitating disease. Here the authors used combination of mechanics and small-angle X-ray diffraction to study the effects of immediate and selective removal of the particular domains of fast MyBP-C on sarcomere structure and function in permeabilized skeletal muscle. They concluded that the MyBP-C domains play an important role in contractile performance.
News
BioCAT resumes user operations
BioCAT is very excited to be welcoming users back to the facility starting in February. If you are interested in beam time next run, please contact the appropriate beamline scientist.
Register for MuscleX 4 Symposium
We are pleased to announce the fourth BioCAT MuscleX symposium. The symposium will feature an introductory presentation on BioCAT’s scientific missions, new capabilities enabled by recent upgrades to the APS source and to the BioCAT beamline, and a series of talks highlighting recent muscle studies utilizing X-ray diffraction or other structural techniques. The workshop will take place from 5/15/2025 to 5/16/2025 and will be entirely virtual (via Zoom). A Zoom link will be provided to registered participants at a later time, prior to the symposium.
BioCAT Town Hall Wrap-Up
BioCAT held a town hall on January 10th to discuss upgrades to the beamline over the APS-U dark period and the resumption of user operations in February. Videos of the town hall, as well as slides, and a summary of the announcements are now available.