BioCAT is a mature user facility that supports several types of experiments.
One measure of the facility’s scientific impact is the number and quality of the
publications produced. As of October 2023, the facility and its users had
published more than 600 articles, which had been cited more than 28,000 times
with an average number of citations per article around 46.
A list of all BioCAT publications can be found in the APS database
When you publish your science from BioCAT, please follow
BioCAT organizes occasional topic focused science workshops (in contrast to our
more general training workshops). Videos from lectures at these workshop are listed below
MuscleX 3: Sarcomeric regulation mechanisms in health and disease
Below is a gallery of a few of BioCAT’s science highlights.
New Resource for the Muscle Diffraction Community
BioCAT staff have just published a review article, Ma & Irving, 2022 Int.
J. Mol. Sci. 2022, 23(6), 3052, on
the use of small angle X-ray fiber diffraction for studying skeletal and
cardiac muscle disease. The article consists of a guided tour of the
various diffraction features that can be used to extract specific pieces
of information that can be used to provide insights into the structural
basis of pathology. The article also contains a comprehensive review of
the literature reporting diffraction studies of muscle that illustrates
how small angle fiber diffraction has increased our understanding of
specific muscle diseases such as hypertrophic cardiomyopathy, dilated
cardiomyopathy, and nemaline myopathy.
What Bacterial Pathogens Can Teach Us about Protein Folding
Protein folding is one of the fascinating unanswered questions in biology.
How does an amino acid sequence that is unfolded when it leaves the
ribosome manage to fold properly into a highly ordered, lightning-fast
enzyme or sturdy structural protein? Why don’t all the proteins in the cell
instead just stick to each other, aggregating into a big mess? A unique
model system in bacteria may hold some of the answers to these questions.
The system involves the study of what are termed autotransporter proteins.
These proteins have a highly specialized protein folding process
that attracted the attention of a team of researchers who have
used this bacterial system as a model to determine what allows these
unique proteins to maintain their disordered state in the periplasm. The
work includes studies carried out at BioCAT. The authors believe their
work will provide important information toward understanding
basic questions of protein folding and tests long-held theories
about how this remarkable biological process works.
Relaxation at the Molecular Level
The molecular interactions between the proteins myosin and actin that
generate force during muscle contraction are some of the most well-studied
molecular interactions in biology. However, there are some congenital
skeletal muscle disorders and types of heart failure where relaxation of
the muscle, rather than the force generation part of the cycle, appears
to be the problem, and there are currently no available treatments that
affect relaxation specifically. Recent work conducted at BioCAT used a unique
transgenic mouse model, time-resolved small-angle x-ray diffraction, and
molecular dynamics simulations to discover more about how myosin and actin
interact during skeletal muscle relaxation. This research may help
identify new treatments for neuromuscular disorders associated with impaired
muscle relaxation kinetics.
Understanding the Physiology of the Human Heart through the Study of Tarantula Muscles
A research team has found an unlikely source of inspiration
for understanding how the human heart works and how we might design better
drugs for conditions like hypertrophic cardiomyopathy: tarantulas. The
source of nightmares for arachnophobes and the household pets for
arachnophiles are inspiring researchers to take new approaches to
understanding diseases that alter how heart muscle cells contract and relax.
But, before getting to the human heart, there is more to learn about the
physiology of tarantula muscles. The researchers set out to understand how
contractions in tarantula muscle cells are activated and why are muscle
twitches that follow a sustained muscle contraction (post-tetanic) more
forceful than those that don’t (pre-tetanic). Their results provide
evidence that phosphorylation, the chemical addition of a phosphoryl
group (PO3-) to an organic molecule, plays a key role in muscle activation
and post-tetanic potentiation (PTP) in tarantula muscles.
Key Insights into an Inherited Muscle Disease
The gene NEB encodes for the skeletal muscle protein nebulin. Mutations in NEB
cause the disease nemaline myopathy, which is one of the more common inherited
myopathies. Patients with this muscle disorder have muscle weakness in
multiple different parts of their body and can also experience difficulties with feeding
or breathing. Currently, there is no cure for nemaline myopathy and treatment options
are limited. A team of researchers from the University of Arizona and BioCAT
working to provide new insights into the pathogenesis of this
skeletal muscle disorder, report a new mouse model of nemaline myopathy that exhibits
similar symptoms to those identified in human patients. Importantly,
the new mouse model of this disease can be used to test future therapeutics. Future
studies are warranted to determine if interventions can relieve disease symptoms in
these mice. If successful, such therapeutics could be used for improving the quality of
life in human patients.
Structure-Function Studies Elucidate GPCR-Independent Regulation of G-proteins
Guanine nucleotide binding proteins popularly known as G-proteins,
involved in a variety of cellular signal transduction pathways are
heterotrimeric proteins consisting of α, β, and γ subunits. Ric8A is
known to be both a chaperone for the assembly of the α-subunit of G-proteins,
and a Guanine nucleotide Exchange Factor (GEF). McClelland et al., have
conducted a detailed structural analysis on the complex between Ric8A
and Gαi1 using cryoEM, X-ray crystallography, and SAXS.
Uncovering Unique Structural Features in Protein Regions Associated with ALS
Prion-like domains (PLDs) have become a topic of interest because
of their connection with a variety of debilitating brain diseases, such as amyotrophic
lateral sclerosis (ALS) and frontotemporal dementia. In fact, mutations in PLDs of
some genes have been shown to cause neurodegenerative disease. A recent study using
data obtained at BioCAT completed a comprehensive biophysical investigation of
PLDs in the protein hnRNPA1 to uncover the major behavioral and structural
features of these domains. This meaningful work may lead to discoveries
that can help individuals living with such neurodegenerative diseases.
Sarcomere Structure and Nemaline Myopathy
Nemaline myopathy (NM) is one of the most common congenital non-dystrophic
myopathies and is characterized by severe hypotonia, muscle weakness,
feeding difficulties, respiratory failure, and the presence of nemaline
bodies (rods) in skeletal muscle biopsies. One form of nemaline myopathy
is caused by mutations in the KBTBD13 (NEM6) gene. A combination of
transcranial magnetic stimulation-induced muscle relaxation, muscle fiber-
and sarcomere-contractility assays, super-resolution microscopy, and low
angle X-ray diffraction at BioCAT revealed that the
impaired muscle relaxation kinetics in NEM6 patients are caused by
structural changes in the thin filament, a sarcomeric microstructure.
Structure-Function Understanding of aGPCR ECRs Critical for Drug-Design
Cellular communication mediated by a variety of cell-surface receptors
involves ligand induced conformational changes in the extracellular
region (ECR). A variety of drugs such as cetuximab (Epidermal Growth
Factor Receptor), etrolizumab (Integrins), and erenumab (calcitonin
receptor-like receptor) function by trapping ECRs in specific conformations
and have proved to be effective therapeutic agents in several cancers,
bowel diseases, and migraine. Leon et al., studied a class of
relatively understudied G-protein couple receptors (GPCRs) called
adhesion-GPCRs (aGPCRs) which have a structurally unique ECR with a
diverse set of mechanistic possibilities.
Cool Temperatures During Hibernation May Freeze Muscle Contraction to Save Energy
Striated muscle contraction is a highly regulated process that involves an
orchestrated series of events within the muscle’s contractile units, which
are also known as sarcomeres. In a recent study, researchers studied the
effect of low temperature on mammalian skeletal muscle contraction. They
found that cooler temperatures reduce force generation by trapping
filaments in the muscle sarcomeres in a refractory state that cannot
undergo contraction and utilize adenosine triphosphate (ATP). This
mechanism provides important insight into how hibernating animals may
conserve energy while still allowing vital functions in the body to continue.
Frustration and Folding of a TIM Barrel Protein
In their continuing endeavor to understand misfolding proteins as part of
the etiology of a variety of diseases, the Matthews lab particularly focuses
on the different factors that impede a protein’s path from the unfolded state
to the global free energy minimum. The complexity of the folding trajectory
understandably depends on the size of the protein mostly because of the
formation of intermediates many of which often stall the formation of an
optimal native conformation.
Structure of BS Ric8A, a regulator of G-protein Biology
Ric8A is a well-known
regulator of G-protein biology and belongs to a class of proteins different
from the G protein-coupled receptors (GPCRs), which act via interactions
with monomeric Gα subunits as opposed to heterotrimeric Gαβγ proteins.
SAXS was used in combination with crystallography and biochemical studies
to show that the flexible C-terminal tail is important for the overall
stability of Ric8A and the function as a guanine nucleotide exchange
Probing the Powering of Contractions in Heart Failure
Current treatments can slow progression of heart failure,
but do not address the underlying issues, including specific
problems that cause systolic heart failure. In this condition,
the heart doesn’t contract vigorously enough in pushing blood
into the body’s circulation. But findings at nanometer and
millisecond scales, based upon experimental data collected at
BioCAT may help improve design of therapies directed at motor
proteins to rescue failing hearts.
New Insights into Traumatic Brain Injury
Traumatic brain injury, or TBI, is often referred to as the “invisible
injury” — while on the surface everything seems normal with brain structure,
symptoms may present themselves in the behavior of the injured and cannot
be explained. This work looked at the effect of controlled
amounts of compressive force on rat optic nerves to attempt to identify
the changes that occur in otherwise normal looking brain neurons due to
the specific impact forces experienced during head trauma. As a result
of this ongoing work, researchers have a better understanding
of what kind of experience, or injury, leads to what kind of damage in the
myelin - helping to visualize injuries based on the smallest force
necessary to cause it. This information may be critical to knowing when
someone has an injury after an accident but before symptoms emerge, and
help supports the decision of when and how to treat them.
Mechanistic Insights into Insulin Degrading Enzyme from Laminar-Flow SAXS
Insulin Degrading Enzyme (IDE) is known known to be a significant
factor in the pathophysiology of conditions such as Diabetes
mellitus and Alzheimer’s disease. This paper reveals structural
states present during substrate recognition and capture and
identifies a potential rate limiting step in the reaction.
A Target Mutation that Renders a Cancer Drug Ineffective
Mutations in the gene PTPN11, which encodes a common enzyme
called SHP2, can result in developmental disorders, such as
Noonan Syndrome, and act as oncogenic drivers in patients with
certain blood cancers. Due to the well understood role of the
enzyme SHP2 in Noonan Syndrome and in tumorigenesis, many
companies are currently trying to develop drugs that inhibit
the enzyme. Researched investigated what impact mutations to
SHP2 may have on the potential efficacy of drugs targeting
A Super-relaxed Myosin State to Offset Hypertrophic Cardiomyopathy
Researchers investigated the stabilizing action of mavacamten,
a cardiac drug currently in phase 3 clinical trials, on the
ß-cardiac myosin super-relaxed state and its possible therapeutic
effects on hypertrophic cardiomyopathy.
Unraveling the role of a “nebulous” protein
Nebulin is a protein important to muscle strength, as
mutations can cause the muscles in patients with nemaline
myopathy disease to be weak, little is known about how it
works. Researchers investigated the function of Nebulin in
mice and found that it is necessary for generating physiological
levels of force.
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.
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.
Lafora Disease: A Delicate Solubility Problem
Cells can store up to 55,000 glucose units in water-soluble spheres of branched, polymeric
glycogen. This provides ready energy for rapid response to cellular needs but
also must be managed carefully because too much glycogen accumulation can
activate programmed cell death. This is especially true of neurons, which
consume large amounts of glucose but are particularly sensitive to glycogen
build-up. One example of what can happen when this basic metabolic process
goes awry is observed in Lafora disease, a devastating fatal epilepsy in which
mutations in a single key enzyme result in the formation of insoluble glucan
inclusion bodies that cause neuronal death. Research conducted at two x-ray
beamlines at the U.S. Department of Energy’s Advanced Photon Source (APS), an
Office of Science user facility at Argonne solved the structure of the enzyme
responsible, the laforin glucan phosphatase. The work has provided important
insights into both the basis of Lafora disease and normal glycogen metabolism.
TAPBR: A Novel Protein Chaperone With a Role in Peptide Editing in Immune Recognition
TAP binding protein, related (TAPbPr), a novel protein
chaperone, plays a role in loading peptides onto major
histocompatibility class i (mhc i) molecules during the
process of immune surveillance. Researchers investigated
the biochemical function of TAPbPr, comparing it with
tapasin, another chaperone with a similar protein sequence.
The results of this study could lead to ways to modulate
peptide loading in vaccine design, improving T-cell recognition.
Combating an Infectious Invader
The investigation of the fungal prion HET-s(218-289) provides
insights into the fundamental mechanisms of prion assembly and
propagation of its infectious fold, which is made robust by a
complex and diverse array of inter and intramolecular structural
features. This level of complexity has not been observed in
short-peptide amyloids that have been used as prion model systems.
The cross-bridge spring: cool muscles store elastic energy
The Hawkmoth Manduca sexta is an emerging model system for a
wide range of studies in integrative biology. The flight muscles
are particularly interesting in that, unlike most insect flight
muscle, but like vertebrate skeletal and cardiac muscles, they
are a synchronous muscle where each stimulus generates one muscle twitch.
The Molecular Mechanism of Stretch Activation in Insect Muscle
Flying insects are among the most successful species on our
planet. Flight is very metabolically demanding and many insects
have found a clever way to reduce energy costs in their flight
muscles by employing a process called “stretch activation, which
has been recognized since the 1960s as an interesting and
physiologically important phenomenon, but a mechanistic explanation
has been elusive. Now, research at BioCAT provides another,
important step toward a full explanation of stretch activation,
which also plays an important role in mammalian cardiac
expansion and contraction.
Packing It In: A New Look at Collagen Fibers
Nature uses collagen everywhere in constructing multicellular
animals. There are at least 20 types of collagen, but 80-90% of
the collagen in the body consists of types I, II, and III.
Collagen type II makes up 50% of all cartilage protein, and
is essential in normal formation of such structures as
cartilage, the vitreous humor of the eye (the clear gel
that fills the space between the lens and the retina of
the eyeball of humans and other vertebrates), bones, and
teeth. To create these structures, collagen molecules are
positioned in arrays called fibrils, producing what are known
as the D-periodic fibrillar collagens. Until now, technical
limitations prevented accurate structural studies of collagen
type II packing. A research team aided by the BioCAT 18- ID
beamline and the BioCARS 14-BM-C beamline at the APS has
remedied that situation by determining the molecular structure
of collagen type II in living tissues.
The Power of Proteins: Prion Diseases Demystified
It is hard to believe that a single protein can be responsible
for the damage inflicted by diseases such as human
Creutzfeldt-Jakob and bovine spongiform encephalopathy
(Mad Cow Disease). Yet the implicated protein, known as a
prion and only about 200 amino acids long, can initiate and
propagate a disease cycle just by changing its shape. A
collaborative research team has achieved a significant advance
in our understanding of the infectious power of the prion protein.
Getting to Know Cellulose
As humans continue to deplete the Earth’s supply of fossil fuels,
finding new sources of energy becomes a priority. Biomass, such
as cornhusks left after harvest, is one such alternative energy
source. Before efficient use can be made of such materials,
understanding how to break down cellulose—the fiber in human
nutrition and the main component of much biomass waste—is crucial.
With the help of the NE-CAT and BioCAT beamlines at the APS and
the SPring-8 (Japan) beamline BL38B1, an international research
team from Los Alamos National Laboratory, the University of Tokyo,
and the University of Grenoble has identified important new
features of cellulose structure. Their work provides important
new details that could be used in designing more efficient treatments
for cellulosic biomass.
Filling the Gaps in Collagen Structure
Collagens—we might take them for granted, but without them
there would be no way to build tissues of the heart, skin,
cornea, or bones. In much the same way that wood is used to
frame a house and form a structure for the overlying construction
materials, collagens are proteins used in the framing of mammalian
tissues, but gaining an accurate picture of their three-dimensional
structure in the body has proven more difficult. Thanks to work
by a research group based at the Illinois Institute of Technology
and using the BioCAT 18-ID beamline at the APS, a complete structure
for a collagen molecule—as it actually appears in the extracellular
matrix (ECM)—is now available.
The Correct Signals to Regulate Assembly in Bacteria
By employing x-ray scattering and electron microscopy
researchers using the BioCAT beamline were able to describe
—in stunning detail— a novel two-component mechanism for
assembling a protein associated with bacterial transcription.
Their work greatly advances our understanding of what happens
in normal and, by inference, diseased cells.
Storing the Power to Fly
Fruit flies beat their wings faster than their cellular
powerplants can generate the energy needed for flapping.
To resolve this energetic discrepancy, researchers used the
BioCAT beamline to obtain a series of x-ray photographs that
revealed the flies’ secret: A muscle protein used to power wings
acts like a spring, storing energy while stretched before
snapping back. Not only did this finding surprise researchers
who study muscle, but the results might also help scientists
better understand the human heart.