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In the mid-1950s, Atoms for Peace provided a crucial boost for the study of nuclear physics in Hungary, a country that fell under Communist rule and Soviet domination after World War II. Several small, insulated centers of nuclear research already existed, but after President Dwight Eisenhower's speech to the United Nations General Assembly on 3 December 1953, calling for the development of Atoms for Peace programs, Hungary's efforts began to grow quickly. In the glow of the moment, with significant support from the government and the ruling Communist party, Hungarian physicists established new research centers, bought and constructed instruments, published specialized books and journals, held conferences, and organized university courses and programs to train experts both at home and in the USSR. These activities constituted a new, vibrant nuclear culture encompassing diverse areas of life (agriculture, medicine, and some parts of industry) and eventually some cooperative links with Western and Soviet-bloc scientific communities. [ABSTRACT FROM AUTHOR]

Peroxiredoxins catalyze the reduction of peroxides, a process of vital importance to survive oxidative stress. A nucleophilic cysteine, also known as the peroxidatic cysteine, is responsible for this catalytic process. We used the Mycobacterium tuberculosis alkyl hydroperoxide reductase E (MtAhpE) as a model to investigate the effect of the chemical environment on the specificity of the reaction. Using an integrative structural (R116A – PDB URL URL="HTTP://XLINK.RSC.ORG/?PDB=4XIH"4XIH/URL; F37H – PDB URL URL="HTTP://XLINK.RSC.ORG/?PDB=5C04"5C04/URL), kinetic and computational approach, we explain the mutational effects of key residues in its environment. This study shows that the active site residues are specifically oriented to create an environment which selectively favours a reaction with peroxides. [ABSTRACT FROM AUTHOR]

The mutant E270A of Thermus thermophilus 3-isopropylmalate dehydrogenase exhibits largely reduced (~1%) catalytic activity and negligible activation by K+ compared to the wild-type enzyme. A 3-4 kcal/mol increase in the activation energy of the catalysed reaction upon this mutation could also be predicted by QM/MM calculations. In the X-ray structure of the E270A mutant a water molecule was observed to take the place of K+. SAXS and FRET experiments revealed the essential role of E270 in stabilisation of the active domain-closed conformation of the enzyme. In addition, E270 seems to position K+ into close proximity of the nicotinamide ring of NAD+ and the electron-withdrawing effect of K+ may help to polarise the aromatic ring in order to aid the hydride-transfer. [ABSTRACT FROM AUTHOR]

The three-dimensional structure of the enzyme 3-isopropylmalate dehydrogenase from the bacterium Thermus thermophilus in complex with Mn2+, its substrate isopropylmalate and its co-factor product NADH at 2.0 Å resolution features a fully closed conformation of the enzyme. Upon closure of the two domains, the substrate and the co-factor are brought into precise relative orientation and close proximity, with a distance between the C2 atom of the substrate and the C4N atom of the pyridine ring of the co-factor of approximately 3.0 Å. The structure further shows binding of a K+ ion close to the active site, and provides an explanation for its known activating effect. Hence, this structure is an excellent mimic for the enzymatically competent complex. Using high-level QM/ MM calculations, it may be demonstrated that, in the observed arrangement of the reactants, transfer of a hydride from the C2 atom of 3-isopropylmalate to the C4N atom of the pyridine ring of NAD+ is easily possible, with an activation energy of approximately 15 kcal·mol−1. The activation energy increases by approximately 4-6 kcal·mol−1 when the K+ ion is omitted from the calculations. In the most plausible scenario, prior to hydride transfer the ε-amino group of Lys185 acts as a general base in the reaction, aiding the deprotonation reaction of 3-isopropylmalate prior to hydride transfer by employing a low-barrier proton shuttle mechanism involving a water molecule. Database Structural data have been submitted to the Protein Data Bank under accession number . [ABSTRACT FROM AUTHOR]

In the early history of surface chemistry, in the 1920s, the nature of gas adsorption was a pivotal subject. A theory created by Michael Polanyi in the peripheral Hungary contradicted the received view originating from the American Irving Langmuir. When working out his theory, Polanyi had not even heard of Langmuir's rival description. However, Polanyi emigrated from Hungary to Germany, the centre of his field, and tried to defend his adsorption theory in the circle of the leading experts, including Einstein and Fritz Haber. This controversy seemed vital to his survival as a scientist and as an immigrant. The aim of this article is to recapitulate this controversy, with its sad undercurrents, the role of local science, methods of argumentation, and the work of a central scientific community. [ABSTRACT FROM AUTHOR]

The article discusses Hungarian radiochemist George Hevesy and his research on radioactivity in Hungary during the 1910s. The author asserts that scientific methodology in the study of radioactivity during the period was based on the scientific legacies evolving from either natural history or experiment-based scientific research, sometimes called Baconian science. Other subjects considered are Hevesy's relationships with other scientists in Hungary, the development of the radioactive tracer method, the first applications of radioactive tracers and indicators, the isotope theory of matter, and radioactivity expert Béla Szilárd.

Textbooks and encyclopedias represent different genres of scientific literature. Textbooks help the students to prepare for their examinations in various subjects taught at schools, such as logic, metaphysic, chemistry. In the 17th Century some Calvinist professors, mostly in Germany, thought that a universal wholeness should be taught for the students. Encyclopedias adequately expressed this vision. Some of these professors, including Johannes Alsted, were invited to Hungary, Transylvania, to introduce the encyclopedic spirit to the local schools. This act fostered the first textbook in Hungarian language written by János Apáczai Csere. This book was an encyclopedia born mostly in the Netherlands where the author studied. The Cartesian philosophy combined with a Ramist system served as the basis of the book. Its history shows how the local conditions influence the content of knowledge incorporated into a textbook. [ABSTRACT FROM AUTHOR]

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