The three-dimensional structure of the skeletal muscle voltage-gated L-type calcium channel (Ca(v)1.1; dihydropyridine receptor, DHPR) was determined using electron cryo-microscopy and single-particle averaging. The structure shows a single channel complex with an approximate total molecular mass of 550 kDa, corresponding to the five known subunits of the DHPR, and bound detergent and lipid. Features visible in our structure together with antibody labeling of the beta and alpha(2) subunits allowed us to assign locations for four of the five subunits within the structure. The most striking feature of the structure is the extra-cellular alpha(2) subunit that protrudes from the membrane domain in close proximity to the alpha(1) subunit. The cytosolic beta subunit is located close to the membrane and adjacent to subunits alpha(1), gamma and delta. Our structure correlates well with the functional and biochemical data available for this channel and suggests a three-dimensional model for the excitation-contraction coupling complex consisting of DHPR tetrads and the calcium release channel.
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http://dx.doi.org/10.1016/s0022-2836(03)00899-4 | DOI Listing |
J Virol
December 2024
Université Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.
Bacteriophages are viruses infecting bacteria. The vast majority of them bear a tail, allowing host recognition, cell wall perforation, and DNA injection into the host cytoplasm. Using electron cryo-microscopy (cryo-EM) and single particle analysis, we determined the organization of the tail proximal extremity of siphophage T5 that possesses a long flexible tail and solved the structure of its tail terminator protein p142 (TrP).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599.
Adaptor protein complex-3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 adopts a constitutively open conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question.
View Article and Find Full Text PDFNat Commun
November 2024
School of Biochemistry, Faculty of Health and Life Sciences, Biomedical Sciences Building, University Walk, University of Bristol, BS8 1TD, Bristol, UK.
J Struct Biol
December 2024
Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA. Electronic address:
Apoferritin (apoF) is commonly used as a test specimen in single-particle electron cryo-microscopy (cryo-EM), since it consistently produces density maps that go to 3 Å resolution or higher. When we imaged apoF with a laser phase plate (LPP), however, we observed more severe particle-to-particle variation in the images than we had previously thought to exist. Similarly, we found that images of ribulose bisphosphate carboxylase/oxygenase (rubisco) also exhibited a much greater amount of heterogeneity than expected.
View Article and Find Full Text PDFActa Neuropathol
November 2024
Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
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