1,721,356 research outputs found
Ivano Bertini 1940–2012
No full textIvano Bertini was one of a kind. You could always tell when he was near, as his booming voice made the walls tremble and everyone within them take notice. He loved life and his friends with a passion that is rarely seen. Finding he had lung cancer, he fought bravely but passed away on 7 July of this year. In his scientific life, he took biological inorganic chemistry to new heights with the development of powerful new NMR methods to study paramagnetic metalloproteins. And, equally importantly to us and to many others, he and his beautiful wife, Renata, were lovable, caring and fiercely loyal friends
Ivano Bertini (1940–2012), Biological Inorganic Chemistry Pioneer, An Obituary-Tribute
No full textAfter a four-month battle with lung cancer, Ivano Bertini, Professor of Chemistry and the founder and
soul of the Magnetic Resonance Center (CERM) at the Università degli Studi di Firenze, Florence, Italy, where
he was scientifically active until the end, died on July 7, 2012. A globally recognized pioneer in the field of
biological inorganic chemistry, which he greatly enriched by developing powerful new NMR methods to study
paramagnetic metalloproteins, he was immensely interested in the role of inorganic chemistry in biology. His
influential 2007 book, Biological Inorganic Chemistry, introduced many young persons to the field. This article,
co-authored with his closest collaborators, reviews his life, career, contributions, honors, and legacy
Expression and purification of the human Calmodulin target Endothelial Differentiation-related Factor 1
No full textEndothelial differentiation-related factor1 (EDF-1) encodes a 16-kDa polypeptide, characterized by the presence of a conserved region of about 20 amino acids, the IQ motif, usually presents in CaM-binding domains1. EDF-1 serves two main functions in endothelial cells: it regulates CaM availability in the cytosol, and it acts in the nucleus as a transcriptional coactivator2. Modulators of calmodulin are potential therapeutic targets 3, so their structural and functional characterization is of great interest. With this work we present the protocol that we have optimized to obtain an NMR sample of EDF-1 and the preliminary screening of the protein folding. The gene coding for EDF-1 has been cloned into pETG20A (Invitrogen), that contains the DNA fragments coding for the fusion tag Trx-(his)6. E. coli host strain used for expression of EDF-1 was BL21 Codon plus. Protein expression has been induced with Isopropil β-thiogalactopiranoside (IPTG) and protein purification of EDF-1, produced in inclusion bodies, has been obtained with a denaturation-refolding step on the nickel chelate column. The correct folding of the final sample, without its fusion tag, has been verified by monodimensional and bidimensional HSQC NMR spectra. At present structural determination is under progress
Principal component analysis of conformational states within the EF-hand protein superfamily
No full textThe EFh domain is comprised of a pair of calcium binding EFh motifs, tethered together by a linker of variable length, each motif having a helix-loop-helix structure (Figure). It is one of the most successful metal binding domains in the whole proteome, with more than six hundred EFh domains annotated in the human genome alone. The variety of functions which EFh proteins are involved in is reflected in almost a continuum of conformational states occupied by the domain, under various conditions of calcium or peptide binding.
Looking for recognizable structural patterns, derived by reducing the essential features to simple descriptors, permits a classification of the types of conformations (or conformational changes) that are significant for the functional role associated to
calcium binding. We find that the two most meaningful linear combinations (PC1 and PC2 scores) of the six interhelical angles, obtained using a standard Principal Component Analysis
(PCA) approach, are able to describe the system retaining 80% of the ability to describe the structure and the structural changes within the EFh protein superfamily.
Members of different protein families are identified by their characteristic movements in the PC1-PC2 plane upon
calcium or peptide binding. New structures can be easily assigned to specific families by their PC1-PC2 scores under various conditions
A Serine → Cysteine Ligand Mutation in the High Potential Iron−Sulfur Protein from Chromatium vinosum Provides Insight into the Electronic Structure of the [4Fe−4S] Cluster
No full textWe have succeeded in preparing a mutant of the High Potential Iron-Sulfur Protein (HiPIP) from Chromatium vinosum in which a cysteine ligand has been replaced by a serine (C77S). Proton chemical shift data and nuclear Overhauser effects indicate that structural perturbations induced by the C77S mutation are minimal in both the oxidized and reduced forms of the HiPIP. The reduction potential of C77S is 25 mV lower than that of the wild-type HiPIP (WT) (0.2 M ionic strength, pH 4.5-9.0, 25 degrees C). Assignment of the hyperfine shifted signals in the H-1 NMR spectrum of oxidized C77S revealed that the temperature dependences of the signals associated with cluster-ligating residues 46 and 77 are Curie and and-Curie type, respectively, and are thus the reverse of those in WT. Taken together, these observations indicate that the iron bound to Ser-77 is less reducible than the corresponding iron in WT. The results are consistent with a previous model of the electronic structure of oxidized HiPIP clusters, confirming the presence of an equilibrium between two species of differing valence distributions. The current results permit the extension of this model to predict the relative reduction potentials of the individual iron ions in the oxidized HiPIPs up to now investigated
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