Precise regulation of calcium homeostasis is essential for many physiological functions. The Ca2+-selective transient receptor potential (TRP) channels TRPV5 and TRPV6 play vital roles in calcium homeostasis as Ca2+ uptake channels in epithelial tissues. Detailed structural bases for their assembly and Ca2+ permeation remain obscure. Here we report the crystal structure of rat TRPV6 at 3.25 Å resolution. The overall architecture of TRPV6 reveals shared...
Tag Archives: Crystal
Crystal structure of the human sterol transporter ABCG5/ABCG8
ATP binding cassette (ABC) transporters play critical roles in maintaining sterol balance in higher eukaryotes. The ABCG5/ABCG8 heterodimer (G5G8) mediates excretion of neutral sterols in liver and intestines. Mutations disrupting G5G8 cause sitosterolaemia, a disorder characterized by sterol accumulation and premature atherosclerosis. Here we use crystallization in lipid bilayers to determine the X-ray structure of human G5G8 in a nucleotide-free state at 3.9 Å resolution,...
The crystal structure of Cpf1 in complex with CRISPR RNA
The CRISPR–Cas systems, as exemplified by CRISPR–Cas9, are RNA-guided adaptive immune systems used by bacteria and archaea to defend against viral infection. The CRISPR–Cpf1 system, a new class 2 CRISPR–Cas system, mediates robust DNA interference in human cells. Although functionally conserved, Cpf1 and Cas9 differ in many aspects including their guide RNAs and substrate specificity. Here we report the 2.38 Å crystal structure of the...
Interface dynamics and crystal phase switching in GaAs nanowires
Controlled formation of non-equilibrium crystal structures is one of the most important challenges in crystal growth. Catalytically grown nanowires are ideal systems for studying the fundamental physics of phase selection, and could lead to new electronic applications based on the engineering of crystal phases. Here we image gallium arsenide (GaAs) nanowires during growth as they switch between phases as a result of varying growth...
Crystal structures of the M1 and M4 muscarinic acetylcholine receptors
Muscarinic M1–M5 acetylcholine receptors are G-protein-coupled receptors that regulate many vital functions of the central and peripheral nervous systems. In particular, the M1 and M4 receptor subtypes have emerged as attractive drug targets for treatments of neurological disorders, such as Alzheimer’s disease and schizophrenia, but the high conservation of the acetylcholine-binding pocket has spurred current research into targeting allosteric sites on these receptors. Here...
Crystal structure of a substrate-engaged SecY protein-translocation channel
Hydrophobic signal sequences target secretory polypeptides to a protein-conducting channel formed by a heterotrimeric membrane protein complex, the prokaryotic SecY or eukaryotic Sec61 complex. How signal sequences are recognized is poorly understood, particularly because they are diverse in sequence and length. Structures of the inactive channel show that the largest subunit, SecY or Sec61α, consists of two halves that form an hourglass-shaped pore with...
Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light
Chiral nematic liquid crystals—otherwise referred to as cholesteric liquid crystals (CLCs)—are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel...
Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light
Chiral nematic liquid crystals—otherwise referred to as cholesteric liquid crystals (CLCs)—are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel...
Crystal structure of eukaryotic translation initiation factor 2B
Eukaryotic cells restrict protein synthesis under various stress conditions, by inhibiting the eukaryotic translation initiation factor 2B (eIF2B). eIF2B is the guanine nucleotide exchange factor for eIF2, a heterotrimeric G protein consisting of α-, β- and γ-subunits. eIF2B exchanges GDP for GTP on the γ-subunit of eIF2 (eIF2γ), and is inhibited by stress-induced phosphorylation of eIF2α. eIF2B is a heterodecameric complex of two copies...
Crystal structure of a DNA catalyst
Catalysis in biology is restricted to RNA (ribozymes) and protein enzymes, but synthetic biomolecular catalysts can also be made of DNA (deoxyribozymes) or synthetic genetic polymers. In vitro selection from synthetic random DNA libraries identified DNA catalysts for various chemical reactions beyond RNA backbone cleavage. DNA-catalysed reactions include RNA and DNA ligation in various topologies, hydrolytic cleavage and photorepair of DNA, as well as...