Chemistry International
Vol. 21, No. 6, November 1999

1999, Vol. 21
No. 6 (November)
.. 40th Council Highlights
.. IUPAC: 2000 and Beyond
.. 37th IUPAC Congress
.. Chemistry in Today's Brazil
.. News from IUPAC:
   Biodegradation of
   Chemical Warfare
   Agents
.. Other Societies
.. New Books and Publications
.. Provisional Recommendations
.. Awards
.. Conference Announcements
.. Conferences

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Chemistry International
Vol. 21, No. 6
November 1999


37th IUPAC Congress-27th GDCh General Meeting

14-19 August 1999,
Berlin, Germany

This extremely successful event, held at Berlin's International Congress Center (ICC) with the general theme "Frontiers in Chemistry: Molecular Basis of the Life Sciences", celebrated the 80th anniversary of the founding of IUPAC and the 50th anniversary of the refounding of the Gesellschaft Deutscher Chemiker (GDCh) after World War II. More than 2 400 participants (most from outside Germany) from 55 countries had the opportunity to attend about 350 talks (in up to 12 parallel sessions) and to view about 1 200 posters. Over 250 attendees from developing or economically disadvantaged countries were sponsored, at least in part, by substantial reductions in registration fees.

Prof. Dr.
Thomas R. Cech

Eight plenary lecturers, including four Nobel Prize winners, headlined an array of leading chemists from around the world reporting on their latest research findings in medicine, agriculture, nutrition, and the environment. The first plenary speaker, Prof. Dr. Thomas R. Cech (1989 Nobel Prize winner) of the Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA, discussed "RNA in Catalysis: Ribozymes and Telomerase". He showed how some RNA molecules called ribozymes fold to form active sites for biochemical reactions in the complete absence of proteins, while other cellular catalysts are ribonucleoprotein (RNP) particles that contain essential protein and RNA components. He used as an example the crystal structure of the Tetrahymena ribozyme to show how RNA can fold to form a preorganized active site, much like a protein enzyme. His recent work has extended the scope of RNA catalysis via use of in vitro selection-amplification and a combinatorial library of RNA sequences to find ribozymes that catalyze (106-fold) peptidyl transfer between aminoacyladenosine and a second amino acid. He also demonstrated how the RNP enzyme telomerase, responsible for synthesizing the ends of chromosomes in eukaryotes, is attracting much attention because of its roles in cellular immortality and in cancer. Prof. Cech's work combines genetic and biochemical approaches to improve our understanding of RNP enzymes.

Prof. Dr.
Stephen J. Lippard


Prof. Dr. Stephen J. Lippard of the Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA, spoke on "The Chemistry of Selective Hydrocarbon Oxidation in Bacteria". He described how methanotrophic bacteria use a soluble methane monooxygenase (sMMO) system of proteins to convert methane selectively to methanol in the first chemical step required for carbon assimilation and energy via the reaction CH4 + O2 + NADH + H+ ! CH3OH + H2O + NAD+. His laboratory is engaged in an extensive program to understand all aspects of this reaction through studies of sMMO from Methylococcus capsulatus (Bath) as well as through the synthesis and characterization of synthetic model compounds. Prof. Lippard's work has employed X-ray crystallography and high resolution NMR spectroscopy to elucidate the structures of the enzymes and proteins involved. Depending on the relative concentrations of the regulatory protein, reductase, and hydrocarbon substrate, the sMMO system can function alternatively as an oxidase or hydroxylase. From analysis of steady state kinetic and isothermal titration calorimetry data, Prof. Lippard has proposed a model in which the reductase and coupling protein bind noncompetitively at distinct interacting sites on the hydroxylase during catalysis.

Prof. Dr. Roald Hoffman (left) receives an Honorary Membership from Prof. Dr. Erhard Meyer-Galow, President of the German Chemical Society (Gesellschaft Deutscher Chemiker).


Prof. Dr. Roald Hoffman (1981 Nobel Prize winner) of the Department of Chemistry, Cornell University, Ithaca, NY, USA, after being made an Honorary Member of the GDCh, delivered a disarmingly delightful lecture entitled "Chemistry in Culture, Culture in Chemistry". In a five-minute introduction presented entirely in German, he declaimed quite movingly that despite having lost three grandparents and his father to the Holocaust by the time he arrived in the United States at the age of eleven, he bears no animosity about the past. This artist, poet, author, andabove allsuperb exponent of applied, theoretical, organic, inorganic, and solid state chemistry then spoke in a most accessible manner of the need for chemists to build bridges to the general public. It is so important, he said, for chemists to teach as widely as possibleand not just in schoolsbecause chemical research is fundamentally about change, and people are at best ambivalent about change and at worst afraid of it. He amplified his point with many fascinating historical examples, most notably the platinum catalyst lamp, designed by Johann Wolfgang Döbereiner (1780-1849), which provided a significant amount of indoor lighting for central Europe during the second quarter of the 19th century. Prof. Hoffmann pointed out that papers about the chemistry of the Döbereiner lamp are still being published today. He also spoke of author-philosopher-poet Johann Wolfgang von Goethe's fascination with chemistry, a topic discussed in more detail in an evening Congress lecture by Prof. Dr. Georg Schwedt, who has written a book on the subject. Prof. Hoffman reminded us that the cultural dimension of chemistry is just as important as the science, and that both must be communicated effectively to the public if chemistry is to prosper.

Prof. Dr.
Heinz A. Staab

 

Prof. Dr. Heinz A. Staab of the Department of Organic Chemistry, Max-Planck-Institut, Heidelberg, Germany, a past president of the GDCh (1984-1985), also was made an Honorary Member before delivering his plenary lecture. He spoke in detail about "Quinone-Porphyrin Interactions". His presentation elucidated the photosynthetic reaction mechanisms of porphyrin donors and quinone acceptors, with many examples of structures and visible absorption spectra.

 

 

 

Prof. Dr.
Sir John E. Walker

Prof. Dr. Sir John E. Walker (1997 Nobel Prize winner) spoke about "How ATP is Made" in the annual Federation of European Chemical Societies (FECS) lecture. His pioneering work on ATP (adenosine triphosphate) synthase, begun in the early 1980s with the aim of ascertaining its detailed chemical structure, has had a significant impact upon the chemical and biological sciences. With Paul Boyer and Jens Skou, he won the 1997 Nobel Prize for Chemistry for his "elucidation of the enzymatic mechanism underlying the synthesis of ATP". Prof. Walker graphically illustrated the importance of ATP synthesis by pointing out that we turn over approximately our entire body weight in ATP every 24 hours. The complexity of the effort in elucidating the structure of the enzyme is apparent from Prof. Walker's demonstration that bovine F1-ATPase consists of nine polypeptide chains with a total molecular weight of 371 765, with each of the substituent chains ranging in molecular weight from 5 652 to 55 264.

Prof. Dr.
Martin Karplus


Prof. Dr. Martin Karplus of the Laboratoire de Chimie Biophysique, Université Louis Pasteur, Strasbourg, France (and Research Professor in the Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA) gave a plenary lecture on "Protein Dynamics: From Femtoseconds to Milliseconds". He presented a brief overview of the use of simulations for studying protein dynamics and presented three examples that involved dynamic phenomena on time scales ranging from femtoseconds to milliseconds. Prof. Karplus described the behavior of the protein and the CO ligand after photodissociation of the myoglobin CO complex. He has investigated catalysis by the enzyme triosephosphate isomerase of the transformation of dihydroxyaldehyde phosphate to glyceraldehyde phosphate, and his work has shown how the enzyme reduces the activation barrier. Prof. Karplus compared the classical dynamics of the reaction in the enzyme with the results expected from transition state theory. His laboratory has employed simulations to determine some general principles of protein folding.

 

Prof. Dr.
Chi-Huey Wong

Prof. Dr. Chi-Huey Wong of the Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA spoke on "Chemical-Enzymatic Synthesis and Glycobiology". He pointed out that of the three major classes of biomoleculesproteins, nucleic acids, and carbohydratesit is carbohydrates that are the least exploited. Despite the important roles that saccharides play in numerous biological recognition events (e.g., bacterial and viral infection, cancer metastasis, and inflammatory reactions), the pace of development of carbohydrate-based therapeutics has been relatively slow. Prof. Wong suggested that this slow pace is further hindered by the lack of practical synthetic and analytical methods available for carbohydrate research and by the problems associated with undesirable properties of carbohydrates as drug candidates. He showed how recent advances in the field, however, have demonstrated that many of these problems can be circumvented with the use of chemo-enzymatic synthetic methods and carbohydrate mimetics, i.e., small molecules that contain the essential functional groups (often with additional hydrophobic or charged groups) to resemble the active conformation of the parent structure.

Prof. Dr.
Robert Huber

 

Prof. Dr. Robert Huber (1988 Nobel Prize winner) of the Max-Planck-Institut für Biochemie, Martinsried, Germany delivered the final plenary lecture at the closing session of the Congress. His topic was "Biomolecular Cages for Protein Folding and for Protein Degradation". He demonstrated how recent crystal structural studies of the Thermosome, an archaeal homolog of the eukaryotic chaperonin CCT, of the yeast 20S proteasome, and of the E. coli HsIV protein, provide detailed views of the subunit structures and arrangements of these large homo- or hetero-oligomeric complexes. All three complexes observed are closed in their respective crystal forms, and the cavities are quite inaccessible from the outside such that substantial rearrangement of segments, domains, or subunits is required for macromolecular substrate entry and binding. Prof. Huber showed that binding of ATP and its analogs induces small local changes and large domain rotations in the thermosome, possibly representing intermediates between closed and open forms in the catalytic cycle, but leaves the overall conformation closed in all crystal forms studies. He pointed out how very detailed structural information is available for proteolysis by the proteasome through small substrate binding studies and mutagenesis experiments that explain the specificity, processivity, and preferred length distribution of its peptide products.

 

 

 

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