Solar energy and its role as the energetic basis of terrestial life continue to attract interest now as ever – and not only in connection with oil crises and the ozone hole! How are light energy and electrons transferred in Nature? Which chemical compounds are required for this purpose? What relationships exist between structure and function? Does the photosynthetic reaction center of bacteria correspond to that of plants? Answers to these and further questions have been found by Robert Huber, Johann Deisenhofer and Hartmut Michel through the extremely meticulous crystallization and X-ray structure analysis of pigment protein systems, for which the three authors were awarded the 1988 Nobel Prize in Chemistry.

Solar energy and its role as the energetic basis of terrestial life continue to attract interest now as ever - and not only in connection with oil crises and the ozone hole! How are light energy and electrons transferred in Nature? Which chemical compounds are required for this purpose? What relationships exist between structure and function? Does the photosynthetic reaction center of bacteria correspond to that of plants? Answers to these and further questions have been found by Robert Huber, Johann Deisenhofer and Hartmut Michel through the extremely meticulous crystallization and X-ray structure analysis of pigment protein systems, for which the three authors were awarded the 1988 Nobel Prize in Chemistry.

How does an organism manage during its lifetime to respond to a huge number of different antigens, even though the number of antibody genes is, of necessity, limited? The Nobel Prize for Medicine was awarded to Susumu Tonegawa in 1987 for providing an answer to this question. Tonegawa discovered that not a single complete gene for an antibody peptide chain is inherited by an organism. Instead, the genetic information in the germ line is contained in several hundred gene segments. Somatic recombination of these gene segments during the differentiation of B lymphocytes results in the production of tens of thousands of complete genes. Somatic hypermutation of these genes leads to further diversification of antibody peptide chains in such a way that B cells that carry immunoglobulin receptors displaying good recognition of specific antigens are selected for in a later phase of B-cell differentiation.

The founders of “supramolecular chemistry” include Charles J. Pedersen, Donald J. Cram, and Jean-Marie Lehn, who shared the Nobel Prize for Chemistry in 1987 for their fundamental research in this area of organic chemistry. Their work focused the attention of many chemists on the cavities formed by certain types of molecules. Cations, anions, or neutral molecules can enter the cavities of specifically designed compounds and are held there by intermolecular forces. It is fully justified, therefore, to compare such compounds to biomolecules. How the development began, how it achieved its first successes, and what fascinating possibilities lie in store for future research are discussed by Pedersen and Cram in this issue and by Lehn in the January issue (page 89 ff.). The most recent results from Lehn's research are also reported, appropriately, in this issue.

That his Nobel lecture might be regarded as a tour through a family album is the view expressed by D. R. Herschbach in a note of thanks to his co-workers. The following citation might serve as a stimulus for reading this lecture: “As urged by my students, on this occasion I want both to view our still youthful field of research from a wider perspective and to recount some favorite instructive episodes from its infancy. I will also briefly discuss several prototype reactions which have served to develop heuristic models and to reveal how electronic structure governs the reaction dynamics.”–Note: The Nobel lectures of Y.-T. Lee and J. C. Polanyi who were awarded the Nobel prize together with D. R. Herschbach, have already appeared in the October issue of the journal.

Which internal degrees of freedom of a reactant influence the reaction probability and what consequences does this have on the course of elementary chemical processes? These questions, whose answers are very important for the understanding of reaction dynamics and for checking the predictions of quantum-mechanical calculations, were addressed by the recipients of the 1986 Nobel Prize for Chemistry—Y. T. Lee, J. C. Polanyi, and D. Herschbach (his Nobel Lecture will appear in the December issue). They studied reactions by using the crossed molecular beam method or by measurement of IR chemiluminescence and were thereby able to determine the relative orientations of the reactants most favorable for a reactive collision, to prove some proposed reaction mechanisms to be invalid, to detect and interpret unexpectedly small activation energies, and to clarify the nature of the energy transfer between reactants and products.

Which internal degrees of freedom of a reactant influence the reaction probability and what consequences does this have on the course of elementary chemical processes? These questions, whose answers are very important for the understanding of reaction dynamics and for checking the predictions of quantum-mechanical calculations, were addressed by the recipients of the 1986 Nobel Prize for Chemistry—Y. T. Lee, J. C. Polanyi, and D. Herschbach (his Nobel Lecture will appear in the December issue). They studied reactions by using the crossed molecular beam method or by measurement of IR chemiluminescence and were thereby able to determine the relative orientations of the reactants most favorable for a reactive collision, to prove some proposed reaction mechanisms to be invalid, to detect and interpret unexpectedly small activation energies, and to clarify the nature of the energy transfer between reactants and products.

Growth factors—for nerves and for epidermal tissue—are the areas of research of last year's recipients of the Nobel Prizes for Medicine. The growth of nerves and of epidermal tissue requires a chemical stimulant. Nerve growth factor (NGF) proved to be a freely diffusing protein that is essential for the normal development of embryos, but which, in excess, results in major disruption of neurogenic processes. NGF has been isolated from several sources, including the salivary glands of mice. Crude extracts of NGF had unexpected side effects, the systematic investigation of which led to the discovery of epidermal growth factor (EGF). EGF, like NGF, is a protein, whose sequence has been determined. The primary signal mediated by EGF is thought, at present, to involve the tyrosine kinase activity of its receptor.

Growth factors—for nerves and for epidermal tissue—are the areas of research of last year's recipients of the Nobel Prizes for Medicine. The growth of nerves and of epidermal tissue requires a chemical stimulant. Nerve growth factor (NGF) proved to be a freely diffusing protein that is essential for the normal development of embryos, but which, in excess, results in major disruption of neurogenic processes. NGF has been isolated from several sources, including the salivary glands of mice. Crude extracts of NGF had unexpected side effects, the systematic investigation of which led to the discovery of epidermal growth factor (EGF). EGF, like NGF, is a protein, whose sequence has been determined. The primary signal mediated by EGF is thought, at present, to involve the tyrosine kinase activity of its receptor.

Todays triumphant advance of X-ray structure analysis is due in large part to the development of the “direct methods” by Herbert Hauptman and Jerome Karle. Previously, it was generally assumed to be impossible to determine a structure directly from the diffraction pattern of a crystal, for a normal diffraction experiment afforded only amplitudes, but no phases of the diffraction maxima. This phase problem was overcome in a series of steps that involved recognition that the required phase information was contained in the measured intensities, the derivation of a foundation mathematics that displayed relationships between phases and magnitudes and even among phases alone and, finally, the development of practical methods for structure determination, strategies that brought together in a more or less optimal fashion the mathematical relationships with suitably adjusted and refined experimental data.

Todays triumphant advance of X-ray structure analysis is due in large part to the development of the “direct methods” by Herbert Hauptman and Jerome Karle. Previously, it was generally assumed to be impossible to determine a structure directly from the diffraction pattern of a crystal, for a normal diffraction experiment afforded only amplitudes, but no phases of the diffraction maxima. This phase problem was overcome in a series of steps that involved recognition that the required phase information was contained in the measured intensities, the derivation of a foundation mathematics that displayed relationships between phases and magnitudes and even among phases alone and, finally, the development of practical methods for structure determination, strategies that brought together in a more or less optimal fashion the mathematical relationships with suitably adjusted and refined experimental data.

How does the healthy organism regulate cholesterol metabolism? The answer to this question was obtained, inter alia, by studies on patients with a genetic disease, familial hypercholesterolemia. Michael S. Brown and Joseph L. Goldstein recognized thereby the key role of the receptor for the cholesterol-transport protein LDL. The receptor is a well-characterized protein; studies afforded insights into endocytosis and the pathway by which the receptors enter and leave the cell. Genetic defects in the LDL receptors give rise to an accumulation of cholesterol in plasma and premature arteriosclerosis.

The trick to preparing monoclonal antibodies on a large scale consists in fusing mouse myeloma (tumor) cells with mouse spleen cells that have previously been exposed to an antigen. The hybridoma cells having the desired characteristics are immortal and secrete antibodies with a single specificity. Georges Köhler, who received the 1984 Nobel Prize for Physiology and Medicine, developed this hybridoma technique together with C. Milstein. The number of applications is legion.

The basic concepts of immunology and their development as part of biology during the last 100 years is the starting point of Niels K. Jerne's lecture, which he presented on the occasion of accepting the 1984 Nobel Prize for Physiology and Medicine. Each half of an antibody molecule consists of a light polypeptide chain containing about 214 amino acid residues and a heavy polypeptide chain containing a little more than 400 amino acid residues.

A solid phase as “protecting group” in peptide synthesis—this was the original idea of Bruce Merrifield, who received the 1984 Nobel Prize for Chemistry. In his lecture, he describes the development of the Merrifield synthesis. In principle, all difunctional educts that may be selectively protected at one end and activated at the other can undergo reactions on solid supports.