The interaction of myosin with actin filaments is the central feature of muscle contraction and cargo movement along actin filaments of the cytoskeleton. The energy for these movements is generated during a complex mechanochemical reaction cycle. Crystal structures of myosin in different states have provided important structural insights into the myosin motor cycle when myosin is detached from F-actin. The difficulty of obtaining diffracting...
Tag Archives: resolution
Charge-density analysis of an iron–sulfur protein at an ultra-high resolution of 0.48 Å
The fine structures of proteins, such as the positions of hydrogen atoms, distributions of valence electrons and orientations of bound waters, are critical factors for determining the dynamic and chemical properties of proteins. Such information cannot be obtained by conventional protein X-ray analyses at 3.0–1.5 Å resolution, in which amino acids are fitted into atomically unresolved electron-density maps and refinement calculations are performed under strong...
Tracing haematopoietic stem cell formation at single-cell resolution
Haematopoietic stem cells (HSCs) are derived early from embryonic precursors, such as haemogenic endothelial cells and pre-haematopoietic stem cells (pre-HSCs), the molecular identity of which still remains elusive. Here we use potent surface markers to capture the nascent pre-HSCs at high purity, as rigorously validated by single-cell-initiated serial transplantation. Then we apply single-cell RNA sequencing to analyse endothelial cells, CD45− and CD45+ pre-HSCs in...
Near-atomic resolution visualization of human transcription promoter opening
In eukaryotic transcription initiation, a large multi-subunit pre-initiation complex (PIC) that assembles at the core promoter is required for the opening of the duplex DNA and identification of the start site for transcription by RNA polymerase II. Here we use cryo-electron microscropy (cryo-EM) to determine near-atomic resolution structures of the human PIC in a closed state (engaged with duplex DNA), an open state (engaged with...
Seattle startup Algorithmia builds front desk AI inspired by Mark Zuckerberg’s New Year’s resolution
This year, Facebook CEO Mark Zuckerberg made a New Year’s resolution to build an artificial intelligence that helps out at work and...
Crystallography: Resolution beyond the diffraction limit
A method has been devised that extends the resolution of X-ray crystal structures beyond the diffraction limit. This might help to improve the visualization of structures of proteins that form 'poorly diffracting' crystals. See Letter p.202
Nature 530 168 doi: 10.1038/530168a
Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 Å resolution
U4/U6.U5 tri-snRNP represents a substantial part of the spliceosome before activation. A cryo-electron microscopy structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at 3.7 Å resolution led to an essentially complete atomic model comprising 30 proteins plus U4/U6 and U5 small nuclear RNAs (snRNAs). The structure reveals striking interweaving interactions of the protein and RNA components, including extended polypeptides penetrating into subunit interfaces. The invariant ACAGAGA sequence...
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What are you sick of losing? Maybe your keys always seem to be in a coat pocket you didn’t know you had? Maybe you’re a frequent travel but your luggage looks like everyone else’s and you’re always picking up the wrong bag at...