ALBERT

Description: Specific heat C M ( T ) of polycrystalline Dy 0.6 Y 0.4 Rh 4 B 4 and Dy 0.6 Y 0.4 Rh 3.85 Ru 0.15 B 4 was studied in the temperature range of 0.5–9 K and magnetic fields 0–10 kOe for the first time. It was found that the λ-anomaly in the specific heat exists at T c ≈ 6 K for Dy 0.6 Y 0.4 Rh 4 B 4 and at T c ≈ 6.6 K for Dy 0.6 Y 0.4 Rh 3.85 Ru 0.15 B 4. It is suppressed in a magnetic field and shifted to lower temperatures. Partial substitution of Rh by Ru enhances superconductivity, presumably, due to stronger inner magnetism of the dysprosium sublattice in Dy 0.6 Y 0.4 Rh 4 B 4 as compared with Dy 0.6 Y 0.4 Rh 3.85 Ru 0.15 B 4 . Furthermore, it was observed that the molar heat capacity C M ( T ) of Dy 0.6 Y 0.4 Rh 3.85 Ru 0.15 B 4 increases with decreasing temperature for T 〈 4 K. In Dy 0.6 Y 0.4 Rh 4 B 4 , an increase in C M ( T ) with decreasing temperature is accompanied by the appearance of a maximum at T max = 1.5 K, which might be a manifestation of the magnetic phase transition in the dysprosium subsystem at this temperature.

Description: The electrical resistance of polycrystalline Dy 0.6 Y 0.4 Rh 3.85 Ru 0.15 B 4 is measured for the first time near the superconducting transition temperature ( T c 1/2 ≈ 6.66 K) in various inclined magnetic fields (φ = 0, 45, and 90°) and plots are made of R ( T ) and the upper critical field in dimensionless units h *( t ). These dependences exhibit strong anisotropy with respect to the transport current through a sample when the orientation of the magnetic field is changed from φ = 0 to 90°. This appears to be related to texturing of the polycrystals. An analysis of the R ( T ) and h *( t ) curves shows that the magnetic field suppresses the superconducting state more strongly at φ = 45° than at the other angles of inclination. The h *( t ) dependences are analyzed in terms of the Werthamer-Helfand-Hohenberg theory and the Maki parameter α and the spin-orbital scattering parameter λ SO are estimated. It is shown that for φ = 0 and 90°, α = 0 and λ SO = 0 and only the orbital contribution is observed, while for φ = 45°, α = 4.2 and λ SO = 0 and there is a substantial increase in the relative contribution of spin paramagnetic effects. It is suggested that the character of the R ( T ) and h *( t ) curves in inclined magnetic fields is influenced by the effect on the superconducting state of the internal magnetism of the dysprosium atoms, which depends on the inclination of the field.

Description: G-protein-coupled receptors (GPCRs) signal primarily through G proteins or arrestins. Arrestin binding to GPCRs blocks G protein interaction and redirects signalling to numerous G-protein-independent pathways. Here we report the crystal structure of a constitutively active form of human rhodopsin bound to a pre-activated form of the mouse visual arrestin, determined by serial femtosecond X-ray laser crystallography. Together with extensive biochemical and mutagenesis data, the structure reveals an overall architecture of the rhodopsin-arrestin assembly in which rhodopsin uses distinct structural elements, including transmembrane helix 7 and helix 8, to recruit arrestin. Correspondingly, arrestin adopts the pre-activated conformation, with a approximately 20 degrees rotation between the amino and carboxy domains, which opens up a cleft in arrestin to accommodate a short helix formed by the second intracellular loop of rhodopsin. This structure provides a basis for understanding GPCR-mediated arrestin-biased signalling and demonstrates the power of X-ray lasers for advancing the frontiers of structural biology.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521999/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521999/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kang, Yanyong -- Zhou, X Edward -- Gao, Xiang -- He, Yuanzheng -- Liu, Wei -- Ishchenko, Andrii -- Barty, Anton -- White, Thomas A -- Yefanov, Oleksandr -- Han, Gye Won -- Xu, Qingping -- de Waal, Parker W -- Ke, Jiyuan -- Tan, M H Eileen -- Zhang, Chenghai -- Moeller, Arne -- West, Graham M -- Pascal, Bruce D -- Van Eps, Ned -- Caro, Lydia N -- Vishnivetskiy, Sergey A -- Lee, Regina J -- Suino-Powell, Kelly M -- Gu, Xin -- Pal, Kuntal -- Ma, Jinming -- Zhi, Xiaoyong -- Boutet, Sebastien -- Williams, Garth J -- Messerschmidt, Marc -- Gati, Cornelius -- Zatsepin, Nadia A -- Wang, Dingjie -- James, Daniel -- Basu, Shibom -- Roy-Chowdhury, Shatabdi -- Conrad, Chelsie E -- Coe, Jesse -- Liu, Haiguang -- Lisova, Stella -- Kupitz, Christopher -- Grotjohann, Ingo -- Fromme, Raimund -- Jiang, Yi -- Tan, Minjia -- Yang, Huaiyu -- Li, Jun -- Wang, Meitian -- Zheng, Zhong -- Li, Dianfan -- Howe, Nicole -- Zhao, Yingming -- Standfuss, Jorg -- Diederichs, Kay -- Dong, Yuhui -- Potter, Clinton S -- Carragher, Bridget -- Caffrey, Martin -- Jiang, Hualiang -- Chapman, Henry N -- Spence, John C H -- Fromme, Petra -- Weierstall, Uwe -- Ernst, Oliver P -- Katritch, Vsevolod -- Gurevich, Vsevolod V -- Griffin, Patrick R -- Hubbell, Wayne L -- Stevens, Raymond C -- Cherezov, Vadim -- Melcher, Karsten -- Xu, H Eric -- DK071662/DK/NIDDK NIH HHS/ -- EY005216/EY/NEI NIH HHS/ -- EY011500/EY/NEI NIH HHS/ -- GM073197/GM/NIGMS NIH HHS/ -- GM077561/GM/NIGMS NIH HHS/ -- GM095583/GM/NIGMS NIH HHS/ -- GM097463/GM/NIGMS NIH HHS/ -- GM102545/GM/NIGMS NIH HHS/ -- GM103310/GM/NIGMS NIH HHS/ -- GM104212/GM/NIGMS NIH HHS/ -- GM108635/GM/NIGMS NIH HHS/ -- P30EY000331/EY/NEI NIH HHS/ -- P41 GM103310/GM/NIGMS NIH HHS/ -- P41GM103393/GM/NIGMS NIH HHS/ -- P41RR001209/RR/NCRR NIH HHS/ -- P50 GM073197/GM/NIGMS NIH HHS/ -- P50 GM073210/GM/NIGMS NIH HHS/ -- R01 DK066202/DK/NIDDK NIH HHS/ -- R01 DK071662/DK/NIDDK NIH HHS/ -- R01 EY011500/EY/NEI NIH HHS/ -- R01 GM087413/GM/NIGMS NIH HHS/ -- R01 GM109955/GM/NIGMS NIH HHS/ -- S10 RR027270/RR/NCRR NIH HHS/ -- U54 GM094586/GM/NIGMS NIH HHS/ -- U54 GM094599/GM/NIGMS NIH HHS/ -- U54 GM094618/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Jul 30;523(7562):561-7. doi: 10.1038/nature14656. Epub 2015 Jul 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA. ; Department of Chemistry and Biochemistry, and Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-1604, USA. ; Department of Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA. ; Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany. ; Joint Center for Structural Genomics, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA. ; 1] Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA [2] Department of Obstetrics &Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. ; The National Resource for Automated Molecular Microscopy, New York Structural Biology Center, New York, New York 10027, USA. ; Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458, USA. ; Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA. ; Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada. ; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA. ; Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA. ; 1] Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2] BioXFEL, NSF Science and Technology Center, 700 Ellicott Street, Buffalo, New York 14203, USA. ; 1] Department of Chemistry and Biochemistry, and Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-1604, USA [2] Department of Physics, Arizona State University, Tempe, Arizona 85287, USA. ; 1] Department of Chemistry and Biochemistry, and Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-1604, USA [2] Beijing Computational Science Research Center, Haidian District, Beijing 10084, China. ; 1] Department of Chemistry and Biochemistry, and Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-1604, USA [2] Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA. ; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China. ; Department of Obstetrics &Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. ; Swiss Light Source at Paul Scherrer Institute, CH-5232 Villigen, Switzerland. ; Department of Biological Sciences, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA. ; School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, Ireland. ; 1] BioXFEL, NSF Science and Technology Center, 700 Ellicott Street, Buffalo, New York 14203, USA [2] Ben May Department for Cancer Research, University of Chicago, Chicago, Illinois 60637, USA. ; Laboratory of Biomolecular Research at Paul Scherrer Institute, CH-5232 Villigen, Switzerland. ; Department of Biology, Universitat Konstanz, 78457 Konstanz, Germany. ; Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. ; 1] Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany [2] Centre for Ultrafast Imaging, 22761 Hamburg, Germany. ; 1] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada [2] Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada. ; 1] Department of Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA [2] Department of Biological Sciences, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA [3] iHuman Institute, ShanghaiTech University, 2F Building 6, 99 Haike Road, Pudong New District, Shanghai 201210, China. ; 1] Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA [2] VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26200343" target="_blank"〉PubMed〈/a〉

Description: Active DNA demethylation (ADDM) in mammals occurs via hydroxylation of 5-methylcytosine (5mC) by TET and/or deamination by AID/APOBEC family enzymes. The resulting 5mC derivatives are removed through the base excision repair (BER) pathway. At present, it is unclear how the cell manages to eliminate closely spaced 5mC residues whilst avoiding generation of toxic BER intermediates and whether alternative DNA repair pathways participate in ADDM. It has been shown that non-canonical DNA mismatch repair (ncMMR) can remove both alkylated and oxidized nucleotides from DNA. Here, a phagemid DNA containing oxidative base lesions and methylated sites are used to examine the involvement of various DNA repair pathways in ADDM in murine and human cell-free extracts. We demonstrate that, in addition to short-patch BER, 5-hydroxymethyluracil and uracil mispaired with guanine can be processed by ncMMR and long-patch BER with concomitant removal of distant 5mC residues. Furthermore, the presence of multiple mispairs in the same MMR nick/mismatch recognition region together with BER-mediated nick formation promotes proficient ncMMR resulting in the reactivation of an epigenetically silenced reporter gene in murine cells. These findings suggest cooperation between BER and ncMMR in the removal of multiple mismatches that might occur in mammalian cells during ADDM.

Description: Spontaneous hydrolytic deamination of cytosine to uracil (U) in DNA is a constant source of genome instability in cells. This mutagenic process is greatly enhanced at high temperatures and in single-stranded DNA. If not repaired, these uracil residues give rise to C→T transitions, which are the most common spontaneous mutations...