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In this paper we report the synthesis of new azabicycloalkane scaffolds, which could be exploited to obtain cRGD-based bioconjugates that may find promising application for targeted drug delivery, theranostic, and general cancer-cell labeling. By exploiting a Hosomi-Sakurai intramolecular allylation reaction we efficiently converted a silylated aldehyde precursor into 7,5-fused lactam scaffolds endowed with an exocyclic double bond. The presence of the vinyl function should make it possible to conjugate bioactive compounds to selectively carry them to tumor sites. The optimized synthetic sequence allows the gram-scale preparation of the target scaffolds in a few steps and good 39% overall yield from readily accessible materials. The high reactivity of the exocyclic olefin moiety was ascertained by performing a Heck coupling reaction with 1-bromo-4-nitrobenzene, which gave the corresponding functionalized derivatives in good (80-91%) yields. [ABSTRACT FROM AUTHOR]

Nasu-Hakola disease (NHD) was first reported separately by Nasu and Hakola around the same time in the 1970s. It is an autosomal recessive inherited disorder characterized by progressive dementia and repeated pathological fractures during adolescence. It has recently been demonstrated that NHD is caused by a mutation in the TREM2 or DAP12 gene. The present paper demonstrates the first patient reported by Nasu and reviews NHD. The patient was a man who died at the age 38 years. His family history was unremarkable. There was no abnormal developmental history. At the age of 26, the patient suffered a pathological fracture of the right tibia, and X-ray confirmed bone resorption in the right tibia. As for mental status, the patient tended to be euphoric. After that, bone resorption was also seen in other long bones. At the age of 33, the patient could not walk after suffering a right femoral neck fracture. He was apathetic and exhibited behavioral abnormalities. At the age of 38, he could not move or speak and subsequently died. General pathological examination showed yellow opaque gelatinous substances in the medullary cavities, matching translucent cystic lesions in the femur, tibia, and fibula on X-rays. Light microscopy showed numerous membranocystic changes in the substances. The brain weighed 1050 g. Symmetric systemic cerebral atrophy, in particular atrophy of the cerebral white matter in the occipital and temporal lobes, was confirmed. Histological examination showed white matter degeneration and diffuse sclerosis accompanied by astroglial proliferation. Severe demyelination was confirmed. Axonal degeneration and destruction were marked. In demyelinated areas, fat granule cells appeared, and lipid granule-positive cells aggregated around vessels. Cerebral cortical neurons were relatively maintained. In the brain, no membranocystic lesions could be recognized. In the DAP12 gene, the patient had a conversion of nucleotide at position 116 resulting in serine 38 to asparagine substitution. [ABSTRACT FROM AUTHOR]

A nine-octapeptide insertion in the prion protein (PrP) gene is associated with an inherited form of human prion disease. Transgenic (Tg) mice that express the mouse homolog of this mutation (designated PG14) spontaneously accumulate in their brains an insoluble and weakly protease-resistant form of the mutant protein. This form (designated PG14Spon) is highly neurotoxic, but is not infectious in animal bioassays. In contrast, when Tg(PG14) mice are inoculated with the Rocky Mountain Laboratory (RML) strain of prions, they accumulate a different form of PG14 PrP (designated PG14RML) that is highly protease resistant and infectious in animal transmission experiments. We have been interested in characterizing the molecular properties of PG14Spon and PG14RML, with a view to identifying features that determine two, apparently distinct properties of PrP aggregates: their infectivity and their pathogenicity. In this paper, we have subjected PG14Spon and PG14RML to a panel of assays commonly used to distinguish infectious PrP (PrPSc) from cellular PrP (PrPC), including immobilized metal affinity chromatography, precipitation with sodium phosphotungstate, and immunoprecipitation with PrPC- and PrPSc-specific antibodies. Surprisingly, we found that aggregates of PG14Spon and PG14RML behave identically to each other, and to authentic PrPSc, in each of these biochemical assays. PG14Spon however, in contrast to PG14RML and PrPSc, was unable to seed the misfolding of PrPC in an in vitro protein misfolding cyclic amplification reaction. Collectively, these results suggest that infectious and non-infectious aggregates of PrP share common structural features accounting for their toxicity, and that self-propagation of PrP involves more subtle molecular differences. [ABSTRACT FROM AUTHOR]

Not all proteins form well defined three-dimensional structures in their native states. Some amino-acid sequences appear to strongly favour the disordered state, whereas some can apparently transition between disordered and ordered states under the influence of changes in the biological environment, thereby playing an important role in processes such as signalling. Although important biologically, for the structural biologist disordered regions of proteins can be disastrous even preventing successful structure determination. The accurate prediction of disorder is therefore important, not least for directing the design of expression constructs so as to maximize the chances of successful structure determination. Such design criteria have become integral to the construct-design strategies of laboratories within the Structural Proteomics In Europe (SPINE) consortium. This paper assesses the current state of the art in disorder prediction in terms of prediction reliability and considers how best to use these methods to guide construct design. Finally, it presents a brief discussion as to how methods of prediction might be improved in the future. [ABSTRACT FROM AUTHOR]

We have developed a semi-empirical method to determine the subunit molecular weight of a protein. The method is a minor modification of the Edman degradation and is based on a simple chemical procedure to modify specifically the N-terminal NH2 group. Initially, all NH2 groups, including the ε-NH2 groups of lysine residues and the N-terminal α-NH2 group, are reacted with phenylisothiocyanate and the protein derivative is subjected to one step of the Edman degradation. The newly exposed N terminus is then reacted with radioactively labelled phenylisothiocyanate. A value for the subunit molecular weight can be obtained from an analysis of the incorporated radioactivity and the amount of the protein in the sample. The molecular weight of five different proteins have been determined by this method. Our method is particularly useful for proteins containing lipid or sugar components and also for relatively small peptides. The procedure described in this paper for the specific modification of the N terminus has been found to be a powerful tool for protein sequencing. [ABSTRACT FROM AUTHOR]

A protein is usually classified into one of the following four structural classes: all α, all β, (a + B) and α/β. In this paper, based on the maximum correlation-coefficient principle, a new formulation is proposed for predicting the structural class of a protein according to its amino acid composition. Calculations have been made for a development set of proteins from which the amino acid compositions for the standard structural classes were derived, and an independent set of proteins which are outside the development set. The former can test the self consistency of a method and the latter can test its extrapolating effectiveness. In both cases, the results showed that the new method gave a considerably higher rate of correct prediction than any of the previous methods, implying that a significant improvement has been achieved by implementing the maximum-correlation-coefficient principle in the new method. [ABSTRACT FROM AUTHOR]

This paper experimentally verifies the idea presented earlier that the contact of nonpolar clusters located on the surface of protein molecules with water destabilizes proteins. It is demonstrated that protein stabilization can be achieved by artificial hydrophilization of the surface area of protein globules by chemical modification. Two experimental systems are studied for the verification of the hydrophilization approach. 1. The surface tyrosine residues of trypsin are transformed to aminotyrosines using a two-step modification procedure: nitration by tetranitromethane followed by reduction with sodium dithionite. The modified enzyme is much more stable against irreversible thermoinactivation: the stabilizing effect increases with the number of aminotyrosine residues in trypsin and the modified enzyme can become even 100 times more stable than the native one. 2. α-Chymotrypsin is covalently modified by treatment with anhydrides or chloroanhydrides of aromatic carboxytic acids. As a result, different numbers of additional carboxylic groups (up to five depending on the structure of the modifying reagent) are introduced into each Lys residue modified. Acylation of all available amino groups of α-chymotrypsin by cyclic anhydrides of pyromellitic and mellitic acids results in a substantial hydrophilization of the protein as estimated by partitioning in an aqueous Ficoll-400/Dextran-70 biphasic system. These modified enzyme preparations are extremely stable against irreversible thermal inactivation at elevated temperatures (65-98 °C); their thermostability is practically equal to the stability of proteolytic enzymes from extremely thermophilic bacteria, the most stable proteinases known to date. [ABSTRACT FROM AUTHOR]