1,721,065 research outputs found
Atomic Details of Carbon-Based Nanomolecules Interacting with Proteins
Full text linkSince the discovery of fullerene, carbon-based nanomolecules sparked a wealth of research across biological, medical and material sciences. Understanding the interactions of these materials with biological samples at the atomic level is crucial for improving the applications of nanomolecules and address safety aspects concerning their use in medicine. Protein crystallography provides the interface view between proteins and carbon-based nanomolecules. We review forefront structural studies of nanomolecules interacting with proteins and the mechanism underlying these interactions. We provide a systematic analysis of approaches used to select proteins interacting with carbon-based nanomolecules explored from the worldwide Protein Data Bank (wwPDB) and scientific literature. The analysis of van der Waals interactions from available data provides important aspects of interactions between proteins and nanomolecules with implications on functional consequences. Carbon-based nanomolecules modulate protein surface electrostatic and, by forming ordered clusters, could modify protein quaternary structures. Lessons learned from structural studies are exemplary and will guide new projects for bioimaging tools, tuning of intrinsically disordered proteins, and design assembly of precise hybrid materials
Bow-step and twist conformations and stacking interactions in palladium bipyridine and phenanthroline complexes
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
High-resolution crystal structure of the recombinant diheme cytochrome c fromShewanella baltica(OS155)
No full textMultiheme cytochromes c (cyts c) are c-type cyts characterized by non-standard structural and spectroscopic properties. The relative disposition of the heme cofactors in the core of these proteins is conserved and they can be classified from their geometry in two main groups. In one group the porphyrin planes are arranged in a perpendicular fashion, while in the other they are parallel. Orientation of the heme groups is a key factor that regulates the intramolecular electron transfer pathway. A 16.5 kDa diheme cyt c, isolated from the bacterium Shewanella baltica OS155 (Sb-DHC), was cloned and expressed in E. coli and its structure was investigated by X-ray crystallography. Using high-resolution data (1.14 Å) collected at ELETTRA (Trieste), the crystal structure, with an orthorhombic cell (a = 40.81, b = 42.97, c = 82.07 Å), was solved using the homologous diheme from Rhodobacter sphaeroides (Rs-DHC) as the initial model. The electron density map of the refined structure (Rfact of 13.8% and Rfree of 15.4%) shows a two domain structure connected by a central unstructured region (N72-G87). The Sb-DHC, like its homologue (Rs-DHC), folds into a new cyt c class: the N-terminal globular domain, with its three α-helices, belongs to class I of c-type cyts, while the C-terminal domain includes a rare π-helix. The metal centre of the c-type heme groups is axially coordinated by two His residues and it is covalently bound to the protein through two Cys bonds
Diastereoselective Synthesis of 3,4-trans-Disubstituted Pyrrolidin-2-ones via Conjugate Addition
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Sintesi degli acidi (R)- e (S)-3-pirrolidinacetico attraverso reazioni di Michael intramolecolari
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Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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