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Recent Structure (recent + structure)
Selected AbstractsThe capsid protein of human immunodeficiency virus: intersubunit interactions during virus assemblyFEBS JOURNAL, Issue 21 2009Mauricio G. Mateu The capsid protein (CA) of HIV-1 is composed of two domains, the N-terminal domain (NTD) and the C-terminal domain (CTD). During the assembly of the immature HIV-1 particle, both CA domains constitute a part of the Gag polyprotein, which forms a spherical capsid comprising up to 5000 radially arranged, extended subunits. Gag,Gag interactions in the immature capsid are mediated in large part by interactions between CA domains, which are involved in the formation of a lattice of connected Gag hexamers. After Gag proteolysis during virus maturation, the CA protein is released, and approximately 1000,1500 free CA subunits self-assemble into a truncated cone-shaped capsid. In the mature capsid, NTD,NTD and NTD,CTD interfaces are involved in the formation of CA hexamers, and CTD,CTD interfaces connect neighboring hexamers through homodimerization. The CA,CA interfaces involved in the assembly of the immature capsid and those forming the mature capsid are different, at least in part. CA appears to have evolved an extraordinary conformational plasticity, which allows the creation of multiple CA,CA interfaces and the occurrence of CA conformational switches. This minireview focuses on recent structure,function studies of the diverse CA,CA interactions and interfaces involved in HIV-1 assembly. Those studies are leading to a better understanding of molecular recognition events during virus morphogenesis, and are also relevant for the development of anti-HIV drugs that are able to interfere with capsid assembly or disassembly. [source] Stratabound Rayleigh convection observed in a 4D hydrothermal reactive transport model based on the regional geological evolution of Allermöhe (Germany)GEOFLUIDS (ELECTRONIC), Issue 3 2007M. KÜHN Abstract We investigated stratabound Rayleigh convection as a means of transport for leaching of solutes from salt diapirs, their dissipation into the Rhaetian sandstone aquifer and subsequent precipitation of anhydrite with resulting cementation. Reactive transport modelling has been conducted in the context of the recent structure of the Allermöhe site and its palaeogeological development. Resulting flow fields depict large (km-scale) stratabound Rayleigh convection. However, our simulations show the vicinity of the Allermöhe well as a potential area of anhydrite dissolution in contrast to field observations, with precipitation concentrated elsewhere. [source] Muscarinic toxins: tools for the study of the pharmacological and functional properties of muscarinic receptorsJOURNAL OF NEUROCHEMISTRY, Issue 5 2009Denis Servent Abstract Muscarinic receptors mediate metabotropic actions of acetylcholine in the CNS and PNS and autocrine functions of acetylcholine in non-neuronal systems. Because of the lack of highly selective muscarinic ligands, the precise location, functional role, and roles in various diseases of the five muscarinic receptor subtypes remain unclear. Muscarinic toxins isolated from the venom of Dendroaspis snakes have a natural high affinity and selectivity, associated with roles as competitive antagonists, allosteric modulators, and potential agonists. These toxins may therefore be invaluable tools for studying muscarinic receptors. We review data on the structural and pharmacological characterization of the muscarinic toxins, focusing on recent structure,function studies on toxin,receptor interactions. We discuss the potential benefits of using these toxins for investigating muscarinic function in vivo. [source] Formation and reorientation of structure in the surge-type glacier Kongsvegen, SvalbardJOURNAL OF QUATERNARY SCIENCE, Issue 3 2002John Woodward Abstract Kongsvegen, a surge-type glacier in Spitsbergen, Svalbard, shares a tide-water margin with the glacier Kronebreen. The complex has been in retreat since a surge advance of Kongsvegen around 1948. The surface of Kongsvegen displays suites of deformational structures highlighted by debris-rich folia. These structures are melting out to form a network of sediment ridges in the grounded terminal area. The structures are also visible in a marginal, 1 km long, 5,20 m high cliff-face at the terminus. Current models for the evolution of deformational structures at Kongsvegen divide the structures into suites based on their orientation and dip, before assigning a mechanism for genesis based on structure geometry. Interpretation of aerial photographs and field mapping of surface structures suggest that many structures were reorientated or advected during the surge. We suggest that many of the deformational structures highlighted by debris-rich folia represent reorientated, sediment-filled crevasses. Some evidence of thrusting is apparent but the process is not as ubiquitous as previously suggested. Many deformational structures also appear to have been offset by more recent structures. Mechanisms of structural development must, therefore, be considered within the context of distinct stages of glacier flow dynamics and multiple surge episodes. Furthermore, evidence for thrusting and folding within the glacier systems of Svalbard has been used as the basis for interpreting Quaternary glacial landforms in the UK. The findings of this paper, therefore, have implications for interpretations of the Quaternary record. Copyright © 2002 John Wiley & Sons, Ltd. [source] A glossary of DNA structures from A to ZACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2003Anirban Ghosh The right-handed double-helical Watson,Crick model for B-form DNA is the most commonly known DNA structure. In addition to this classic structure, several other forms of DNA have been observed and it is clear that the DNA molecule can assume different structures depending on the base sequence and environment. The various forms of DNA have been identified as A, B, C etc. In fact, a detailed inspection of the literature reveals that only the letters F, Q, U, V and Y are now available to describe any new DNA structure that may appear in the future. It is also apparent that it may be more relevant to talk about the A, B or C type dinucleotide steps, since several recent structures show mixtures of various different geometries and a careful analysis is essential before identifying it as a `new structure'. This review provides a glossary of currently identified DNA structures and is quite timely as it outlines the present understanding of DNA structure exactly 50,years after the original discovery of DNA structure by Watson and Crick. [source] | ||||||||||