摘要:

AbstractAdvances in methodology in both chemistry and molecular biology allow us to take a fresh look at protein science. Chemical synthesis of peptides and site‐directed mutagenesis are now standard research tools, paving the way for the construction of new proteins with tailor‐made structural and functional properties. The decisive hurdle on the way lies not in the synthesis of the molecules proper but rather in a better understanding of the complex folding pathways of polypeptide chains into spatially well‐defined structures. Can the chemist use his synthetic tools tobypassthe notorious “folding problem?” In this article, we present a new approach developed in our laboratory, which opens a chemical route to artificial proteins with predetermined three‐dimensional structures, allowing a first step towards the synthesis of new proteins with functional

ISSN:0570-0833    

DOI:10.1002/anie.198905353

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractMany quinones and their precursors, which are transformed oxidatively into quinones and/or quinone methides, are important natural products. As secondary metabolites, they frequently possess antibiotic and cytotoxic activities, in addition to acting sometimes as pathogens. Several plants and animals, especially insects, use quinonoid substances for defense, often with spectacular results. On the macromolecular level, quinone methides have a key role in the plant kingdom in lignin biosynthesis; the biosynthesis of melanoproteins exemplifies the reactions ofo‐quinones in the animal kingdom. In insects, cross‐linking of structural proteins through quinones and quinone methides results in the construction of the sclerotized exoskeleton. For mankind, the reactivity of quinones in biological systems has far‐reaching consequences of pharmaceutical, toxicological, and technical relevance. The examples in this review show that a common principle underlies these reactions, namely, the chemical modification of biopolymers. As demonstrated particularly well in a more detailed discussion of the chemical principles of insect cuticle sclerotization, several major and important new results have emerged from the development and applications of modern methods of sample separation and from solid‐state NMR spect

ISSN:0570-0833    

DOI:10.1002/anie.198905551

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractCould there be chiral methane? What is the characteristic structural feature (in a physicochemical sense) of a molecule? This question dates back toLouis Pasteur, the discoverer of molecular chirality, and since the work ofvan't HoffandLe Belis generally considered by chemists as solved. In the present article it is pointed out that there exist fundamentally conflicting theoretical views of the physical origin of molecular chirality. These views predict consequences that could, in principle, be distinguished experimentally, but at present there is no conclusive experimental evidence available. Possible experiments are suggested that test different hypotheses. The importance of the magnitude of the parity‐violating energy difference δEPVin molecules due to the weak nuclear force for both the structure and spectra of chiral molecules and for the kinetics of racemization is discussed. The chemical relaxation rate coefficient of chiral molecules with some appreciable energy of excitation is derived for several limiting cases of a simple statistical mechanical model, which takes ΔEPVinto acco

ISSN:0570-0833    

DOI:10.1002/anie.198905711

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198905871

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198905881

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198905901

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198905931

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198905951

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractFor corrigendum see DOI:10.1002/anie.198910741

ISSN:0570-0833    

DOI:10.1002/anie.198905971

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198906001

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY