Structure of rabbit liver fructose 1,6-bisphosphatase at 2.3 Å resolution

The three-dimensional structure of the R form of rabbit liver fructose 1,6-bisphosphatase (Fru-1,6-Pase; E.C. 3.1.3.11) has been determined by a combination of heavy-atom and molecular-replacement methods. A model, which includes 2394 protein atoms and 86 water molecules, has been refined at 2.3 Å resolution to a crystallographic R factor of 0.177. The root-mean-square deviations of bond distances and angles from standard geometry are 0.012 Å and 1.7°, respectively. This structural result, in conjunction with recently redetermined amino-acid sequence data, unequivocally establishes that the rabbit liver enzyme is not an aberrant bisphosphatase as once believed, but is indeed homologous to other Fru-1,6-Pases. The root-mean-square deviation of the C atoms in the rabbit liver structure from the homologous atoms in the pig kidney structure complexed with the product, fructose 6-phosphate, is 0.7 Å. Fru-1,6-Pases are homotetramers, and the rabbit liver protein crystallizes in space group I222 with one monomer in the asymmetric unit. The structure contains a single endogenous Mg<sup>2+</sup> ion coordinated by Glu97, Asp118, Asp121 and Glu280 at the site designated metal site 1 in pig kidney Fru-1,6-Pase R-form complexes. In addition, two sulfate ions, which are found at the positions normally occupied by the 6-phosphate group of the substrate, as well as the phosphate of the allosteric inhibitor AMP appear to provide stability. Met177, which has hydrophobic contacts with the adenine moiety of AMP in pig kidney T-form complexes, is replaced by glycine. Binding of a non-hydrolyzable substrate analog,<sup> β</sup>-methyl-fructose 1,6-bisphosphate, at the catalytic site is also examined

La Francigena nella Lunigiana medievale: una strada da percorrere?

Analisi delle problematiche legate allo studio della Francigena in area lunigianes

Hospitality and the Ethics of Improvisation in the Work of Ingemar Lindh

Ingemar Lindh's work on the principles of collective improvisation has crucial implications for the history of twentieth-century laboratory theatre. His early work with Étienne Decroux and Jerzy Grotowski contributed to the development of a unique practice that resists directorial montage, fixed scores, and choreography; and the ethical dimension that accompanies Lindh's research on collective improvisation is illuminating for a more holistic understanding of the technical and aesthetic considerations in theatre. In this article, Frank Camilleri discusses some of the key aspects of this dimension, notably the dynamics of hospitality and encounter that inform Lindh's approach and the question of responsibility in the actor's work. Frank Camilleri is Lecturer in Drama and Theatre Studies at the University of Kent. From 2004 to 2008 he was Academic Coordinator of Theatre Studies at the University of Malta. He is also Artistic Director of Icarus Performance Project – an ongoing research laboratory that investigates the intermediary space between training and performance processes. Camilleri's work with Lindh in the mid-1990s was instrumental for the development of this research practice

A Direct Interconversion: d-Fructose 6-Phosphate Sedoheptulose 7-Phosphate and d-Xylulose 5-Phosphate Catalyzed by the Enzymes Transketolase and Transaldolase

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Natural history and risk factors for diabetic kidney disease in patients with T2D: lessons from the AMD-annals

The Associazione Medici Diabetologi (AMD) annals initiative is an ongoing observational survey promoted by AMD. It is based on a public network of about 700 Italian diabetes clinics, run by specialists who provide diagnostic confirmation and prevention and treatment of diabetes and its complications. Over the last few years, analysis of the AMD annals dataset has contributed several important insights on the clinical features of type-2 diabetes kidney disease and their prognostic and therapeutic implications. First, non-albuminuric renal impairment is the predominant clinical phenotype. Even though associated to a lower risk of progression compared to overt albuminuria, it contributes significantly to the burden of end-stage renal disease morbidity. Second, optimal blood pressure control provides significant but incomplete renal protection. It reduces albuminuria but there may be a J curve phenomenon with eGFR at very low blood pressure values. Third, hyperuricemia and diabetic hyperlipidemia, namely elevated triglycerides and low HDL cholesterol, are strong independent predictors of chronic kidney disease (CKD) onset in diabetes, although the pathogenetic mechanisms underlying these associations remain uncertain. Fourth, the long-term intra-individual variability in HbA1c, lipid parameters, uric acid and blood pressure plays a greater role in the appearance and progression of CKD than the absolute value of each single variable. These data help clarify the natural history of CKD in patients with type 2 diabetes and provide important clues for designing future interventional studies

Extracellular release of the ‘differentiation enhancing factor’, a HMG1 protein type, is an early step in murine erythroleukemia cell differentiation

AbstractDifferentiation enhancing factor (DEF) is a 29 kDa protein expressed in murine erythroleukemia (MEL) cells and active in promoting a significant increase in the rate of hexamethylenebisacetamide induced differentiation of these cells. The factor was recently shown to possess an amino acid sequence identical to that reported for one of the HMG1 proteins, designated as ‘amphoterin’ on the basis of its highly dipolar sequence. In the present study, we have expressed DEF cDNA in an E. coli strain and found that the recombinant protein has functional properties identical to those observed with native DEF. Furthermore, we demonstrate that, following MEL cell stimulation with the chemical inducer, DEF is secreted in large amounts in the extracellular medium. In fact, the N-terminal sequence and the partial amino acid sequence of tryptic peptides from the secreted protein correspond to those of DEF isolated from the soluble fraction of resting MEL cells. These results are indicative for an extracellular localization as the site of action of DEF and suggest a novel function for proteins belonging to the HMG1 family. Finally, the early decay of DEF mRNA, in chemical induced MEL cells, support the hypothesis that the involvement of the enhancing factor occurs and is completed in the early phases of cell differentiation

Antihypertensive Treatment in Diabetic Kidney Disease: The Need for a Patient-Centered Approach

Diabetic kidney disease affects up to forty percent of patients with diabetes during their lifespan. Prevention and treatment of diabetic kidney disease is currently based on optimal glucose and blood pressure control. Renin-angiotensin aldosterone inhibitors are considered the mainstay treatment for hypertension in diabetic patients, especially in the presence of albuminuria. Whether strict blood pressure reduction entails a favorable renal outcome also in non-albuminuric patients is at present unclear. Results of several clinical trials suggest that an overly aggressive blood pressure reduction, especially in the context of profound pharmacologic inhibition of the renin-angiotensin-aldosterone system may result in a paradoxical worsening of renal function. On the basis of this evidence, it is proposed that blood pressure reduction should be tailored in each individual patient according to renal phenotype

Molecular and Functional Properties of a Calpain Activator Protein Specific for μ-Isoforms

A natural calpain activator protein has been isolated from bovine brain and characterized in its properties and molecular structure. The protein is a homodimer with a molecular mass of about 30 kDa and results in being almost identical to UK114 goat liver protein. Significant similarities with mouse HR12 protein were also observed, whereas a lower degree of similarity was found with a family of heat-responsive proteins named YJGF and YABJ from Haemophilus influenzae and Bacillus subtilis, respectively. The brain activator expresses a strict specificity for the mu-calpain isoform, being completely ineffective on the m-calpain form. As expected, also UK114 was found to possess calpain-activating properties, indistinguishable from those of bovine brain activator. A protein showing the same calpain-activating activity has been also isolated from human red cells, indicating that this factor is widely expressed. All these activators are efficient on mu-calpain independently from the source of the proteinase. The high degree of specificity of the calpain activator for a single calpain isoform may be relevant for the understanding of sophisticated intracellular mechanisms underlying intracellular proteolysis. These data are indicating the existence of a new component of the Ca2+-dependent proteolytic system, constituted of members of a chaperonin-like protein family and capable of promoting intracellular calpain activation

THE NATURE OF THE AMINO ACID RESIDUES INVOLVED IN THE INACTIVATION OF GLUCONATE 6-PHOSPHATE DEHYDROGENASE BY IODOACETATE.

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Rose Bengal as a Specific Photosensitizer for a Histidine Residue at the Triphosphopyridine Nucleotide Binding Site of 6-Phosphogluconate Dehydrogenase

Rose Bengal is a potent inhibitor of 6-phosphogluconate dehydrogenase from Candida utilis and mediates the photoinactivation of the enzyme. The experiments reported in this paper indicate that photoinactivation occurs only when the dye is bound to the TPN binding site of the enzyme. Since the photoinactivation is correlated to the specific oxidation of only 2 residues of histidine, it can be assumed that this amino acid is located at the TPN binding site of 6-phosphogluconate dehydrogenase. These results are a new application of the technique of active site-specific photooxidation