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ALCOHOL DEHYDROGENASES, ALDEHYDE DEHYDROGENASES, AND RELATED ENZYMES

ALCOHOL 1985年第1期2卷 61-66页

作者： JORNVALL, H KAROLINSKA INST DEPT CHEM IS-10401 STOCKHOLM 60SWEDEN

Several new structures have recently been determined for dehydrogenases which are involved in alcohol metabolism. These structures give new insight into catalytic properties, structure-function relationships, and evolutionary connections. They also explain the structural basis for known metabolic deviations. Among alcohol dehydrogenases, the first primary structures for human enzyme forms have been reported (the β 1 , γ 1 , and “atypical” β-chains). These structures explained functional properties and enzymatic differences, showed separate and parallel events of isozyme divergence, and suggested differential gene activations. Similarly, for aldehyde dehydrogenases, the first cytoplasmic isozyme structures have been reported in man and horse. The data showed positions of functionally important residues, and established clear differences between the mitochondrial and cytoplasmic isozymes of aldehyde dehydrogenase. For sorbitol dehydrogenase, the first complete structure which establishes a relationship with other “long” alcohol dehydrogenases in a scheme exhibiting both structural divergence and functional convergence has also been reported. Finally, glucose dehydrogenase has been structurally linked with sorbitol dehydrogenase, extending the scheme and adding further enzymes to the group of “short” alcohol dehydrogenases.

关键词： Alcohol dehydrogenase Aldehyde dehydrogenase Polyol dehydrogenase Sugar dehydrogenase structure-function relationships Amino acid sequences Reactive residues Mutant enzymes Amino acid exchanges Metal-binding protein ligands

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INTERACTION OF THE ANTI-LEUKEMIC ALKALOID, 2-HYDROXY-3,8,9-TRIMETHOXY-5-METHYLBENZO[C]PHENANTHRIDINE (FAGARONINE), WITH NUCLEIC-ACIDS

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CHEMICO-BIOLOGICAL INTERACTIONS 1983年第3期43卷 323-339页

作者： PEZZUTO, JM ANTOSIAK, SK MESSMER, WM SLAYTOR, MB HONIG, GR CHILDRENS MEM HOSP DIV HAEMATOL CHICAGO IL 60614 USA

The novel alkaloid 2-hydroxy-3,8,9-trimethoxy-5-methylbenzo[c]phenanthridine was isolated from the roots of Fagara zanthoxyloides, an indigenous plant of Ghana, structurally characterized and assigned the trivial name fagaronine. Fagaronine is a potent antileukemic agent. A detailed isolation procedure and the results of studies designed to examine its mechanism of action are reported. Admixture of calf thymus DNA produced a hypsochromic shift in the absorption spectra of fagaronine, with a remarkable increase in intensity in the range of 400 nm. The extent of the spectral alterations were dependent on the concentration of DNA which was added, and clear isosbestic points, indicative of a single mode of interaction, were generated. As determined by gel filtration column chromatography, the DNA-fagaronine complex formed with an association constant of 4.7 .times. 104 M-1 and the maximum extent of binding was 1.0 fagaronine molecule per 4.5 base pairs. Contrary to previous literature reports, the binding of fagaronine was not limited to regions of DNA containing adenine and thymine. Isosbestic points were observed following admixture with poly(dA-dT), as well as poly(dG) .cntdot. poly(dC). The most likely mode of interaction is intercalation. As judged by spectral titrations, fagaronine could also interact with RNA. As compared with single-stranded homopolymers [e.g., poly(A), poly(U)], the interaction with double-stranded species [e.g., poly(A) .cntdot. poly(U), poly(I) .cntdot. poly(C)] was more extensive. Although the spectra differed from those obtained with DNA, single isosbestic points could be generated. Additionally, utilizing Salmonella typhimurium strain TM688, fagaronine was found to be bactericidal but not mutagenic. The bactericidal activity was enhanced .apprx. 1000-fold in the presence of a 9000 .times. g supernatant fraction derived from rat liver and the activating component was further characterized as being heat labile and localized in the microsomal

关键词： Activity modulation with rat liver preparation Bactericidal, cytotoxic and mutagenic potential Isolation Mechanism of action Quantitative interaction with DNA structure-function relationships

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ALCOHOL AND POLYOL DEHYDROGENASES

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PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR 1983年第SUPPL. 1期18卷 67-71页

作者： JORNVALL, H CARLQUIST, M JEFFERY, J KAROLINSKA INST DEPT BIOCHEM 2S-10401 STOCKHOLM 60SWEDEN UNIV ABERDEEN MARISCHAL COLLDEPT BIOCHEMABERDEEN AB9 1ASSCOTLAND

“Long” and “short” alcohol dehydrogenases with different structures and catalytic mechanisms exist and the same sub-grouping appears to apply to polyol dehydrogenases. Mammalian liver sorbitol dehydrogenase is clearly related to “long” alcohol dehydrogenases and has structural properties intermediate between those of mammalian and yeast alcohol dehydrogenases. The amino acid sequence of a large segment of the N-terminal part of a liver sorbital dehydrogenase is now determined and shown to be strictly homologous with the long alcohol dehydrogenases. Seventeen of 93 positions have identical residues among all enzymes compared, defining residues of particular functional significance. Proline and glycine residues suggest largely similar conformations between N-terminal parts of sorbitol dehydrogenase and “long” alcohol dehydrogenases, cysteine and histidine residues suggest a conserved zinc atom at the active site, and other residues correlate with structures of special importance.

关键词： Sorbitol dehydrogenase Alcohol dehydrogenase Dehydrogenases Amino acid sequence Homology Isozymes structure-function relationships

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STRUCTURAL STUDIES OF HORSE LIVER ALCOHOL-DEHYDROGENASE - CO-ENZYME, SUBSTRATE AND INHIBITOR BINDING

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PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR 1983年第SUPPL. 1期18卷 73-81页

作者： EKLUND, H Department of Chemistry and Molecular Biology Swedish University of Agricultural Sciences S-750 07 Uppsala 7 Sweden

Alcohol dehydrogenase from horse liver has been thoroughly investigated with crystallographic methods. Four different crystal forms of the enzyme have been solved and refined. They show that the enzyme exists in two predominant forms. The open form is found in the absence of coenzyme and has two long deep clefts cutting the enzyme in three units. In the closed form of the enzyme these clefts are closed around the coenzyme and subtrate/inhibitor. Although there are large conformational changes in the enzyme, they are mainly restricted to relative movements of the separate domains. The internal structure of these domains is virtually identical in the open and closed forms. The coenzyme is the main cause of the conformational change and binds with a large number of interactions to the enzyme. About 4% of the enzyme surface is covered by the bound coenzyme. The nicotinamide ring is not bound to the active site zinc atom, but puts one surface of the ring in contact with the zinc coordinated cystein sulphur atoms. The oxygen atom of the substrate binds directly to the zinc atom with the rest of the substrate close to the nicotinamide of the coenzyme. Large substrates extend into a 15–20 Å long hydrophobic channel which opens up towards the solution. The widely used inhibitor pyrazole binds as a bridge between the zinc atom and the nicotinamide ring. Pyrazoles substituted in the 4-position are generally strong inhibitors. This can be properly related to the organization of the substrate channel of the enzyme.

关键词： Alcohol dehydrogenase Horse liver structure-function relationships Binding sites

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HOW THE LOSS OF SEVERAL RESIDUES, AT THE LEVEL OF ONE INTERGLOBULE JUNCTION, MODULATES THE LACTATE-DEHYDROGENASE ACTIVITY OF YEAST FLAVOCYTOCHROME-B2 - A STUDY OF THE NICKED ENZYMES RESULTING FROM CLOSTRIPAIN AND TRYPSIN ACTION

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BIOCHIMIE 1982年第7期64卷 509-522页

作者： GERVAIS, M CORAZZIN, S RISLER, Y UNIV PIERRE & MARIE CURIE ENZYMOL PHYSICOCHIM LAB CNRS CTR GENET MOLEC F-91190 GIF SUR YVETTE FRANCE

The native chain of flavocytochrome b2 is folded into 3 globules linked together by 2 protease-sensitive bridges, a and cd. Zone a of H flavocytochrome b2 is the 1st to be cleaved under clostripain action. The .alpha.c and .beta.c fragments thus formed are homologous to .alpha.T and .beta.''T trypsic fragments. The remaining activities of the resulting (.***.c) and (.***.''T) forms are only 25 and 4%, respectively, of the native flavocytochrome b2. The study of the catalytic properties of (.***.''T) and (.***.c) species resulting from the crossed reassociation of the isolated fragments show that the .beta.-type fragment plays a critical role in the catalytic process. A dramatic decrease in activity may be correlated with the loss of 6 amino acid residues at the N-terminal of .beta.c. These amino acids could be involved at the active site, which may be located in the contact zone between .alpha. and .beta.

关键词： cytochrome flavodehydrogenase proteolysis domains structure-function relationships

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The three-dimensional structure of scorpion neurotoxins

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Toxicon 1982年第1期20卷 1-7页

作者： Fontecilla-Camps, Juan C. Almassy, Robert J. Suddath, Fred L. Bugg, Charles E. Comprehensive Cancer Center Institute of Dental Research University of Alabama in Birmingham Birmingham AL 35294 United States

The crystal and molecular structure of a toxin from the scorpion Centruroides sculpturatus has been solved by standard x-ray crystallographic methods at 3 Å resolution. Subsequently, the 3 Å model has been refined and the resolution has been extended to 1.8 Å using the gradient-curvature method. The final reliability index is 0.17. The structure has two and a half turns of α-helix, a three-strand stretch of antiparallel β-sheet and several β-turns. Three of the four disulfide bridges are found in close interaction with the α-helix and β-sheet structures in what constitutes a very rigid part of the molecule. Examination of available scorpion toxin sequences reveals several sections containing invariant and/or semiinvariant amino acids. Many of these residues are found clustered on a rather large flat surface which is also clearly more hydrophobic than other areas on the molecule. These observations suggest that this surface may play a role in the biological action of scorpion toxins. Secondary structure predictions calculated using the method of Dufton and Hider agree well with the x-ray structure. This is also true for other scorpion toxins and reinforces the idea that scorpion toxins are a family of structurally related proteins. © 1982.

关键词： conserved amino acids Scorpion toxins structure predictions structure-function relationships three-dimensional structure x-ray crystallography

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INTERACTIONS OF POLYPEPTIDE HORMONES WITH CELL-MEMBRANE SPECIFIC RECEPTORS - STUDIES WITH INSULIN AND GLUCAGON - MINKOWSKI AWARD LECTURE 1975

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DIABETOLOGIA 1976年第2期12卷 83-100页

作者： FREYCHET, P FAC MED PASTEUR INSERM GRP RECH HORMONES POLYPEPTIDIQUES & PHYSIOPATHOL E F-06034 NICE FRANCE

The binding of insulin and glucagon to sites that possess the specificity and affinity of biologically important receptors has been demonstrated in intact cells and in cell plasma membranes. Hormone-receptor interaction in pathological states has been measured. A binding defect, characterized by a decreased concentration of insulin receptors in cell membranes, has been demonstrated in the obese hyperglycemic mouse and in some other obese states with hyperinsulinism. This defect appears to evolve from environmental rather than genetic influences and may be secondary, at least in part, to the endogenous hyperinsulinemia. Studies of structure-activity relationships with the use of biospecific receptors have allowed delineation of the bioactive region of the insulin molecule and the investigation of the hormone specificity of receptors for peptides that possess structural homologies. [Experiments using rats are discussed.].

关键词： 125I-glucagon binding 125I-insulin binding adenylate cyclase cardiac membranes fat cell membranes glucagon Insulin insulin resistance insulin-dextran-ferritin isolated fat cells isolated liver cells liver membranes modified insulins monoiodoglucagon monoiodoinsulin obese hyperglycémic (ob/ob) mouse obesity plasma membrane polypeptide hormones radioreceptorassay receptor defect receptors structure-function relationships visualization of binding sites

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BILIPROTEINS OF CYANOBACTERIA AND RHODOPHYTA - HOMOLOGOUS FAMILY OF PHOTOSYNTHETIC ACCESSORY PIGMENTS

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 1976年第2期73卷 428-431页

作者： GLAZER, AN APELL, GS HIXSON, CS BRYANT, DA RIMON, S BROWN, DM UNIV CALIF SCH MEDDEPT BIOL CHEMLOS ANGELESCA 90024 UNIV CALIF MOLEC BIOL INSTLOS ANGELESCA 90024

Amino-terminal sequence determinations are reported of the subunits of biliproteins of prokaryotic unicellular and filamentous cyanobacteria and of eukaryotic unicellular red algae. The biliproteins examined, allophycocyanin, C-phycocyanin, R-phycocyanin, b-phycoerythrin, and phycoerythrocyanin, vary with respect to the chemical nature and the number and distribution of the bilin chromophores between the two dissimilar subunits. The amino-terminal sequences fall into two classes, "alpha-type" and "beta-type", with a high degree of homology within each *** those biliproteins where the number of bilin chromophores on the two subunits is unequal, the subunit with the greater number of chromophores has the beta-type amino-acid *** homology also exists between alpha- and beta-type sequences, strongly supporting the view that these arose by gene duplication to give rise to the ancestral alpha- and beta-type genes early in the evolution of the biliproteins. The subsequent generation of the various classes of biliproteins appears to be the result of further gene duplication of the alpha- and beta-type genes, ultimately to give rise to families of polypeptide chains of similar sequence, but varying in the number of chromophore attachment sites and the structure of the chromophores.

关键词： phycobiliproteins amino-terminal sequences evolution structure-function relationships

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COMPARATIVE PROPERTIES OF ANTINEOPLASTIC AGENT, 3-ETHOXY-2-OXOBUTYRALDEHYDE BIS(THIOSEMICARBAZONATO) COPPER(II) AND RELATED CHELATES - LINEAR FREE-ENERGY CORRELATIONS

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BIOINORGANIC CHEMISTRY 1974年第3期3卷 261-277页

作者： WINKELMANN, DA BERMKE, Y PETERING, DH UNIV WISCONSIN DEPT CHEM MILWAUKEE WI 53201 USA

The formation constants, reduction potentials, and kinetics of some redox and substitution reactions are reported for a series of bis(thiosemicarbazonato) copper(II) complexes. Linear free energy correlations are developed using reduction potentials as the independent variable in the correlations. The variation in in vitro tumor cell cytotoxicity elicited by the chelates corresponds well with the distribution of the complexes in these correlations, thereby providing an empirical chemical rationale for these differences in biological activity. The linear free energy relationships suggest the operation of a steric factor in the kinetics of the reactions described.

关键词： Linear free energy correlatins antineoplastic agent comparative chemical and biological properties structure-function relationships

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ULTRASTRUCTURAL STUDIES OF SITE OF ACTION OF RYANODINE ON HEART-MUSCLE

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PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY 1974年第3期347卷 185-198页

作者： PENEFSKY, ZJ CITY UNIV NEW YORK MT SINAI SCH MEDDEPT PHYSIOL10 E 102ND STNEW YORKNY 10029

A correlation has been identified between the sensitivity of cardiac muscle to ryanodine and the presence in the muscle of a transverse tubular system. Thus ryanodine failed to inhibit cardiac contraction in tissues which lack a transverse tubular system such as mammalian fetal heart and batracian heart. In the mammalian newborn the inhibition of contractile tension by ryanodine increased during that period of growth when evidence for a developing T system was apparent in electron micrographs. Concentrations of ryanodine sufficient to inhibit contraction of adult mammalian heart muscle were observed to alter the ultrastructure of the tissue. Ryanodine treatment brought about a separation of the sarcolemma at the level of the Z lines and appeared to cause wrinkling and an apparent evagination of the sarcolemma at sarcomere lengths of 2 μ or less. It is suggested that ryanodine inhibits contraction of adult mammalian heart muscle by dissociating the T tubules from the sarcoplasmic reticulum system and thus uncoupling excitation from contraction.

关键词： Excitation-Contraction Coupling Ryanodine structure-function relationships Transverse Tubules

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