The Correct Signals to Regulate Assembly in Bacteria “You are what you eat” is just another way of saying that input determines output, after some metabolic messing around in between. It's the “in between” that interests biologists, because that is where the difference between healthy and diseased cells can originate. Using the BioCAT 18 ID beam-line at the APS, researchers were able to describe---in stunning detail---a novel two-component mechanism for assembling a protein associated with bacterial transcription. Reaching for answers to questions about the heart Can studying the mechanisms of stretch activation in insect flight muscle help us learn more about the way our hearts function? Researchers using the BioCAT beam-line at the U.S. Department of Energy's Advanced Photon Source think so. What Connects Rat Tails to Cancer and Heart Disease? Innovative synchrotron x-ray research techniques used at APS beamlines have yielded new information on the molecular structure of collagen. Because this ubiquitous protein is involved in the progression of cancer and heart disease, the structural information obtained in this study may help in the fight against these deadly ailments. Storing the Power to Fly Fruit flies beat their wings faster than their cellular powerplants can generate the energy needed for flapping them. To study the mechanism which allows fruit flies to fly, researchers from the California Institute of Technology, IIT, and the University of Vermont used the BioCAT beam-line to obtain a series of x-ray diffraction images which reveals the fruit fly's secret. Atomic Models of Plant Viruses An “Around the Experiment Hall” interview with Amy Kendall from the Gerald Stubbs Lab in the Department of Biological Sciences at Vanderbilt University. Measuring the Efficiency of the Myosin Motor at High Load The sliding filament model of muscle contraction is more than 50 years old, yet theories about the precise mechanisms of the motor funciton still generate controversy. Researchers from Universita di Firenze, Instituto Nazionale di Fisica della Materia, Brandeis University, King's College London, the ESRF, IIT, and ANL used the BioCAT beam-line to take a closer look at the molecular structure of myosin II---the molecular motor in muscle---as it works under various loads. Finding Active Proteins When combinatorial chemistry produces new varieties of reagents, the tricky step is figuring out whether those moleucules will be biochemically active. While there are several methods for finding active molecules, they all have limitations. Researchers at ANL employed wide-angle x-ray scattering (WAXS) at the BioCAT beam-line to develop a method for identifying drug candidates. How Water Molecules are Connected Water may be the most important molecule on Earth, but our understanding of its properties is embarrassingly limited. In ice, water takes on numerous phases and structures that can be studied by means of diffraction techniques. As a liquid, however, water poses a frustrating structural puzzle. Recently, researchesrs from SSRL, BESSY, Stockholm University, Linkoeping Unversity, and Ultrecht University used the BioCAT beam-line to obtain detailed information about water. Grasping the Structure of Insect Muscle Poised to Contract Researchers at BioCAT have achieved the first detailed view of resting muscle filaments poised to contract---a long sought-after window into the biochemical cycle that causes muscle contraction. The group determined the overall structure of insect muscle fibers from x-ray diffraction patterns and performed computer modelling to analyze the data. The Role of Interfilament Spacing in Muscle Fliament Calcium Sensitivity The heart regulates ventricular output in response to changes in ventricular filling, a mechanism known as Frank-Starling's law of the heart. Part of the cellular basis for the law is an increase in myofilament Ca2+ responsiveness upon an increase in sarcomere length. This study investigates how information on sarcomere length is transmitted to myofiliments. The “Second Stalk” of ATP Synthase: Dimerization Domain Structure Hydrolysis of adenosine triphosphate (ATP) drives many of the vast range of energy-consuming processes within a cell. The ATP synthase enzyme is a molecular motor that couples proton movement to ATP synthesis. This study focuses on a model for the isolated dimerization domain of the b subunit of Escherichia coli, derived from solution small-angle x-ray scattering (SAXS) of the dimeric domain and x-ray crystallography of the monomer carried out at BioCAT.