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THE GLASSY STATE PHENOMENON IN APPLICATIONS FOR THE FOOD-INDUSTRY - APPLICATION OF THE FOOD POLYMER SCIENCE APPROACH TO structure-function-relationships OF SUCROSE IN COOKIE AND CRACKER SYSTEMS

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JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 1993年第2期63卷 133-176页

作者： SLADE, L LEVINE, H IEVOLELLA, J WANG, M NABISCO FOODS INC FUNDAMENTAL SCI GRP POB 1944 E HANOVER NJ 07936 USA

This review of the glassy state phenomenon in applications for the food industry comprises two main parts. The first is a broad but brief overview of the so-called 'food polymer science' approach and its importance to food R&D studies of glassy solid and rubbery liquid states and glass transitions in food products and processes. The following elements of this approach are discussed: (i) the glass transition temperature (T(g)) and methods for its measurement in foods: (ii) plasticization by water and its effect on T(g);(iii) the concepts of 'water dynamics' and 'glass dynamics' in non-equilibrium food systems;(iv) Williams-Landel-Ferry kinetics in the rubbery state above T(g), (v) state diagrams;and (vi) the effect of molecular weight on T(g). A comprehensive and up-to-date listing of more than 400 literature references on the glassy state phenomenon and glass transitions in food materials and systems is featured in that part of the paper, and these references are also compiled and tabulated according to specific subject headings. The second part of this review highlights the application of the food polymer science approach in recently reported studies on the structure-function relationships of sucrose in cookie and cracker systems. This part describes (i) the sucrose water state diagram as a tool in understanding cookie and cracker baking;(ii) shortcomings of the traditional AACC sugar-snap cookie method as a test-baking system, in contrast to a new test system based on a model commercial-type wire-cut cookie formula;and (iii) a revealing illustration of sucrose functionality in cookie baking. The review concludes with a word about future prospects.

关键词： GLASSY STATE RUBBERY STATE GLASS TRANSITION GLASS TRANSITION TEMPERATURE FOOD APPLICATIONS structure-function relationships WATER relationships COOKIES CRACKERS COOKIE BAKING MECHANISM SUCROSE STATE DIAGRAM FOOD POLYMER SCIENCE WATER PLASTICIZATION WLF KINETICS

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THE CLASS-II AMINOACYL-TRANSFER-RNA SYNTHETASES AND THEIR ACTIVE-SITE - EVOLUTIONARY CONSERVATION OF AN ATP BINDING-SITE

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JOURNAL OF MOLECULAR EVOLUTION 1995年第5期40卷 499-508页

作者： ERIANI, G CAVARELLI, J MARTIN, F ADOR, L REES, B THIERRY, JC GANGLOFF, J MORAS, D CNRS INST BIOL MOLEC & CELLULAIRESTRUCT BIOL LABUPR 9004F-67084 STRASBOURGFRANCE

Previous sequence analyses have suggested the existence of two distinct classes of aminoacyl-tRNA synthetase. The partition was established on the basis of exclusive sets of sequence motifs (Eriani et al. [1990] Nature 347:203-306). X-ray studies have now well defined the structural basis of the two classes: the class I enzymes share with dehydrogenases and kinases the classic nucleotide binding fold called the Rossmann fold, whereas the class II enzymes possess a different fold, not found elsewhere, built around a six-stranded antiparallel beta-sheet, The two classes of synthetases catalyze the same global reaction that is the attachment of an amino acid to the tRNA, but differ as to where on the terminal adenosine of the tRNA the amino acid is placed: class I enzymes act on the 2' hydroxyl whereas the class II enzymes prefer the 3' hydroxyl group. The three-dimensional structure of aspartyl-tRNA synthetase from yeast, a typical class II enzyme, is described here, in relation to its function. The crucial role of the sequence motifs in substrate binding and enzyme structure is highlighted. Overall these results underline the existence of an intimate evolutionary link between the aminoacyl-tRNA synthetases, despite their actual structural diversity.

关键词： 2 CLASSES OF AMINOACYL-TRANSFER-RNA SYNTHETASES SEQUENCE COMPARISONS HOMOLOGY X-RAY structure structure-function relationships ORIGIN OF AMINOACYL-TRANSFER-RNA SYNTHETASES 2 ANCESTRAL MOLECULES GENETIC CODE

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structure-function-relationships OF THE HEMATOPOIETIC GROWTH-FACTORS

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PROTEINS-structure function AND GENETICS 1992年第1期12卷 1-9页

作者： KAUSHANSKY, K Division of Hematology RM-10 Department of Medicine University of Washington Seattle Washington 98195

The hematopoietic growth factors are a family of glycoproteins involved in the production of blood cells from their bone marrow precursors and in the activation of mature blood cells. Much has been learned about the structural features of these molecules responsible for their characteristic biological activities. Most studies have been based upon mutagenesis strategies of intact polypeptides and on epitope mapping of informative monoclonal antibodies to the growth factors. A more limited amount of physical data is available. This review will summarize these findings, highlight the growing body of evidence suggesting that many of these proteins share common evolutionary origins and structural elements, and hopefully point to the directions being taken for further investigations of these scientifically informative and clinically useful group of proteins.

关键词： HEMATOPOIESIS COLONY-STIMULATING FACTORS structure-function relationships GM-CSF IL-3 HELICAL PROTEINS

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IDENTIFICATION OF functionAL DOMAINS IN THE PLASMA APOLIPOPROTEINS BY ANALYSIS OF INTERSPECIES SEQUENCE VARIABILITY

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JOURNAL OF LIPID RESEARCH 1994年第12期35卷 2212-2222页

作者： WEINBERG, RB Department of Internal Medicine Bowman Gray School of Medicine Winston-Salem NC 27157.

Molecular evolution theory posits that sequence motifs essential for protein function are constrained by selective pressure from changing over long stretches of evolutionary time. Thus, analysis of inter-species amino acid sequence variability, by identifying highly conserved intervals, should predict the location of domains critical for protein function. We have analyzed the amino acid sequences of the mammalian apolipoproteins A-T, A-IV, C-I, C-II, C-III, D, and E with a computer algorithm that calculates numerical residue variability scores. The application of a median sieve filter to the data facilitated identification of the exact boundaries of highly conserved domains, which coincided with the location of known structural features and functional domains in this family of proteins. The analysis also identified highly conserved intervals in every apolipoprotein whose function is unknown at present, but which are candidates for regions with specific functional roles.

关键词： structure-function relationships APOLIPOPROTEINS COMPUTER ANALYSIS PROTEIN EVOLUTION MEDIAN FILTER

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ULTRAFAST MEASUREMENTS OF GEMINATE RECOMBINATION OF NO WITH SITE-SPECIFIC MUTANTS OF HUMAN MYOGLOBIN

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JOURNAL OF MOLECULAR BIOLOGY 1994年第3期238卷 437-444页

作者： PETRICH, JW LAMBRY, JC BALASUBRAMANIAN, S LAMBRIGHT, DG BOXER, SG MARTIN, JL STANFORD UNIV DEPT CHEM STANFORD CA 94305 USA ECOLE POLYTECH ENSTA INSERM U275 OPT APPL LAB F-91128 PALAISEAU FRANCE

Flash photolysis studies of NO recombination to heme proteins offer a direct probe of protein structural changes on the tens of picoseconds timescale where they can be compared with molecular dynamics simulations. The geminate recombination of NO to site-specific mutants of human myoglobin (Mb) was studied following photodissociation of the MbNO form. Single amino acid changes were introduced at positions Val68, His64, Lys45 and Asp60 because motions of residues at these positions are generally regarded as important for the mechanism of ligand binding. In sharp contrast to the properties of simple porphyrin-NO complexes, the rebinding kinetics are found to be non-exponential for all mutants, even in aqueous solution at 298 K. The Val68 and His64 mutants substantially affect the NO rebinding rates but, surprisingly, so do changes on the protein surface that are further away from the iron. These changes in kinetics occur on a tens of picoseconds timescale, and therefore there is either a fast communication between protein residues over quite long distances or there are subtle differences in protein structure that exert great control over the reaction dynamics. Various models for the rebinding kinetics are evaluated. A model-free approach to data analysis using the maximum entropy method is found to be most useful. This analysis shows that the rate distributions are very different for the mutants, but are generally bimodal.

关键词： HUMAN MYOGLOBIN MUTAGENESIS KINETICS structure-function relationships PICOSECOND TIMESCALE

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IMPROVING CYTOCHROME-C function BY PROTEIN ENGINEERING - STUDIES OF SITE-DIRECTED MUTANTS OF THE HUMAN PROTEIN

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JOURNAL OF BIOCHEMISTRY 1994年第4期115卷 693-700页

作者： WALLACE, CJA TANAKA, Y SUNTORY LTD RES CTRINST FUNDAMENTAL RESSHIMAMOTOOSAKA 618JAPAN

We have expressed the gene for human cytochrome c, and six mutants of the native sequence, in yeast defective in its own iso-1-cytochrome c gene. All constructs support strong growth in strict aerobic metabolism, and substantial amounts of protein could be extracted from permeabilized cells. The purified analogs, Cysl4Ala, Gly37Arg, Arg38Lys, Arg38Gly, Gly84Ser, and Thr28Ile,Gly84Ser, were examined for changes in functional properties, since the majority of these residues are strongly or absolutely conserved. Indeed, although growth rates of the host yeast strains were very similar, there was great divergence in both physicochemical and biological properties, which have been rationalized in terms of changes to the stability of the cytochrome fold, and to the dipole moment of the protein. Interestingly, although modification of electrostatic properties in some mutants can apparently produce a twofold increase in electron transfer efficiency, such changes are not evolutionarily acceptable. The ''improvement'' is illusory. We suggest that an associated decrease in the stability of the heme crevice offsets any advantage of increased transfer rates.

关键词： CYTOCHROME C PROTEIN ENGINEERING SITE-DIRECTED MUTAGENESIS structure-function relationships

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INDUCTION OF SOMATIC MUTATIONS IN TRADESCANTIA CLONE-4430 BY 3 PHENYLENEDIAMINE ISOMERS AND THE ANTIMUTAGENIC MECHANISMS OF DIETHYLDITHIOCARBAMATE AND AMMONIUM META-VANADATE

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MUTATION RESEARCH 1994年第2期306卷 165-172页

作者： GICHNER, T LOPEZ, GC WAGNER, ED PLEWA, MJ CONSEJO CIENCIA & TECHNOL ESTADO QUERETARO QUERETAROMEXICO UNIV ILLINOIS INST ENVIRONM STUDIESURBANAIL 61801

Three isomers of the promutagen phenylenediamine at mM concentrations were plant-activated and induced mutation in stamen hairs of Tradescantia clone 4430. The rank order of the mutagenicity of the isomers was: o-phenylenediamine > m-phenylenediamine > p-phenylenediamine with corresponding mutagenic potencies of 5.60, 1.43, and 0.46 mutant stamen hair cells/mu mole, respectively. Diethyldithiocarbamate (DEDTC) and ammonium meta-vanadate (vanadate) repressed the mutagenic activity of o-phenylenediamine (o-PDA) in intact plants. Based on inhibition kinetics and reaction rates, the mechanism of DEDTC antimutagenicity was attributed to the inhibition of peroxidases that are required in the plant activation of o-PDA to mutagenic product(s). Spectrophotometric measurements of equimolar concentrations of o-PDA and vanadate demonstrated that the antimutagenic property of vanadate was mainly due to its reactivity with o-PDA.

关键词： PLANT ACTIVATION PROMUTAGENS AROMATIC AMINES structure-function relationships PEROXIDASES

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PATHWAYS OF LYSOZYME EVOLUTION INFERRED FROM THE SEQUENCES OF CYTOCHROME-B IN BIRDS

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JOURNAL OF MOLECULAR EVOLUTION 1993年第4期37卷 367-379页

作者： KORNEGAY, JR KOCHER, TD WILLIAMS, LA WILSON, AC Department of Molecular and Cell Biology University of California Berkeley USA

A reliable phylogeny relating the major groups of Galliformes was sought in order to shed light on an unusual case of coupled amino acid replacements in the lysozymes c of these birds. The New World quail and the African guinea fowl share a unique trio of amino acids at three internal positions but have been separated phylogenetically by the majority of trees based on morphological characters. Alternative hypotheses based on molecular data have suggested an arrangement that would be more parsimonious with regard to the lysozyme data. The entire mitochondrial cytochrome b gene (1,143 bp) was amplified via the polymerase chain reaction (PCR) and sequenced for nine galliforms and a representative anseriform to provide DNA sequence data for a phylogenetic reconstruction. The mode and tempo of change in these sequences were analyzed to determine the characters most appropriate for phylogenetic reconstruction. Our results place the New World quail outside all other representative game birds except the cracids. Although in conflict with various morphological analyses, this finding is consistent with the results of DNA-DNA hybridization studies. A model to account for the coupled replacements in the lysozymes is presented. Our results also suggest a rapid but ancient radiation among the Galliformes such that the majority of cytochrome b sequence differences among taxa have accumulated on the terminal branches of the reconstructed phylogenetic trees.

关键词： MITOCHONDRIAL DNA EVOLUTIONARY TREES COUPLED CHANGES structure-function relationships NEW WORLD QUAIL GUINEA FOWL BASE COMPOSITION PCR AND DIRECT SEQUENCING

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STRUCTURAL-functionAL CORRELATES OF THE NICOTINIC ACETYLCHOLINE-RECEPTOR AND ITS LIPID MICROENVIRONMENT

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FASEB JOURNAL 1993年第15期7卷 1460-1467页

作者： BARRANTES, FJ UNIV NACL SUR RA-8000 BAHIA BLANCA ARGENTINA

Among the proteins specialized in signal transduction, the nicotinic acetylcholine receptor (AChR) is the best-characterized member of the superfamily of ligand-gated ion channels. Since the early finding of a motionally restricted shell of lipids (annulus) encircling the protein in its native membrane (1), there is growing experimental evidence supporting the notion that this interface region is the locus of a variety of pharmacologically relevant processes, including some of the actions of local anesthetics, steroids, and other lipophilic compounds. Biochemical data on the composition and metabolism of AChR-rich membranes and cells, combined with biophysical data on their structure and dynamics, are beginning to provide information on the nature of the annulus itself Patch-clamp data on cells expressing the AChR protein add another dimension to this knowledge, enabling correlations to be established between the chemical composition of lipid-modified cells and the functional properties of the receptor protein in situ at the single-channel level. The effect of free fatty acids, alcohols, phospholipids, cholesterol, and steroid glucocorticoid hormones on the function of the AChR is reviewed. In the case of steroids, their effects at the single-channel level bear a relationship to their use in pathological conditions of medical relevance, e.g., in the treatment of the disease myasthenia gravis.

关键词： CHOLINERGIC RECEPTOR LIPID-PROTEIN INTERACTIONS ION CHANNELS structure-function relationships

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functionAL ARCHITECTURE OF THE NICOTINIC ACETYLCHOLINE-RECEPTOR - A PROTOTYPE OF LIGAND-GATED ION CHANNELS

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JOURNAL OF MEMBRANE BIOLOGY 1993年第2期136卷 97-112页

作者： DEVILLERSTHIERY, A GALZI, JL EISELE, JL BERTRAND, S BERTRAND, D CHANGEUX, JP INST PASTEUR CNRS UNITE NEUROBIOL MOLEC D1284 25 RUE DR ROUX F-75724 PARIS 15 FRANCE CTR MED UNIV GENEVA DEPT PHYSIOL CH-1211 GENEVA 4 SWITZERLAND

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