Dependence on freezing of the geometry and redox potential of type 1 and type 2 copper sites of Japanese-lacquer-tree (Rhus vernicifera) laccase.

The room-temperature e.p.r. spectrum of the Japanese-lacquer-tree (Rhus vernicifera) laccase shows A parallel (the hyperfine splitting constant) and g parallel values of both the Type 1 and Type 2 Cu appreciably different from those measured at liquid-N2 temperature. The geometry of the sites, as inferred from the room-temperature e.p.r. parameters, is more consistent with their redox properties. A rough correlation is found between A parallel and g parallel values and redox potential of the blue copper in several enzymes.     

Correlations between in vivo resistance to Fusarium and in vitro response to fungal elicitors and toxic substances in carnation

Summary With the aim of ascertaining the existance of a correlation between in vivo resistance to Fusarium oxysporum f. sp. dianthi and in vitro response to fungal elicitors and toxic substances, phenylalanine ammonialyase and phytoalexin accumulation, on one hand, and resistance to culture filtrate, on the other, were assayed in in vitro cultures of three susceptible and four resistant Dianthus caryophyllus cultivars. Cultivars showing varying degrees of resistance in vivo either tolerated higher culture filtrate concentrations (Niki) or showed high PAL activity and phytoalexin production when treated with Fusarium elicitor (Duca), or responded positively to both treatments (Mei-Ling, Pulcino). No such responses were shown in tissue cultures of susceptible cultivars. The differential response to the fungal elicitor seemed to be highly specific as genetic differences between cultivars were not observed in tissue cultures treated with other biotic (Phytophthora infestans) and abiotic (HgCl₂) elicitors.Abbreviations FuCWC cell wall components from Fusarium oxysporum f. sp. dianthi race 2 - PhCWC cell wall components from Phytophthora infestans - PAL phenylalanine ammonia-lyase (EC 4.3.1.5)     

Reactions of bovine serum amine oxidase with NN-diethyldithiocarbamate. Selective removal of one copper ion.

NN-Diethyldithiocarbamate (DDC) was able to bind, at 1.0 mM concentration, only about 50% the Cu(II) ions of bovine plasma amine oxidase. Under reducing conditions, this Cu(II) was removed with inactivation of the enzyme. Up to 90% activity could be recovered by treatment with excess Cu(II). The organic cofactor, sensitive to carbonyl reagents, was reduced in the half-Cu-depleted protein and no longer bound phenylhydrazine. The fully reacted protein, in the presence of 10 mM-DDC, lost 50% Cu(II) upon storage at -20 degrees C, but in this case the residual Cu(II) was in the DDC-bound form and the cofactor was in the oxidized state, as it could still bind phenylhydrazine. In the presence of DDC, the rate of reaction with phenylhydrazine was always low, even at 50% DDC saturation, and all derivatives showed identical modifications of the optical and e.p.r. spectra with respect to the phenylhydrazone of the native protein. It is concluded that the two Cu(II) ions are not equivalent, that removal of a single Cu(II) is sufficient to inhibit the re-oxidation of the organic cofactor, and that both Cu(II) ions are in some way involved in the reaction with phenylhydrazine. After reaction with DDC, the optical and e.p.r. spectra of 63Cu(II)-amine oxidase and of 63Cu(II)-carbonic anhydrase [Morpurgo, Desideri, Rigo, Viglino & Rotilio (1983) Biochim. Biophys. Acta 746, 168-175] are very similar and show distorted equatorial co-ordination to Cu(II) of two sulphur atoms and two magnetically equivalent nitrogen atoms.     

An electron spin resonance study of high spin forms of cobalt(II) bovine carbonic anhydrase

The ESR spectra of bovine Co(II) carbonic anhydrase at 7 K at low and high pH and of the iodide derivative have been analyzed. The spectrum of the low pH form shows axial symmetry whilst that at high pH is rhombically distorted. This anisotropy is still more accentuated in the iodide derivative. The high pH (hydroxyl) form and the iodide derivative are thought to have a tetracoordinate trigonal pyramidal structure, with a fifth more distant axial ligand. The low pH form is consistent with a pseudotetrahedral geometry previously postulated.     

The molecular evolution of the alcohol dehydrogenase and alcohol dehydrogenase-related genes in the Drosophila melanogaster species subgroup

The DNA sequences of the Adh genes of three members of the Drosophila melanogaster species subgroup have been determined. This completes the Adh sequences of the eight species of this subgroup. Two species, D. yakuba and D. teissieri, possess processed Adh pseudogenes. In all of the species of the subgroup, a gene of unknown function, Adhr, is located about 300 bp 3' to Adh. Although this gene is experiencing a higher rate of synonymous substitution than Adh, it is more constrained at the amino acid level. Phylogenetic relationships between all eight members of the melanogaster subgroup have been analyzed using a variety of methods. All analyses suggested that the D. yakuba and D. teissieri pseudogenes have a single common ancestor, rather than evolving independently in each species, and that D. melanogaster is the sister species to D. simulans, D. sechellia, and D. mauritiana. The evolutionary relationships of the latter three species remain equivocal.      

K<Emphasis Type="Italic">i</Emphasis> DoQ: using docking based energy scores to develop ligand based model for predicting antibacterials

Background  

Identification of novel drug targets and their inhibitors is a major challenge in the field of drug designing and development. Diaminopimelic acid (DAP) pathway is a unique lysine biosynthetic pathway present in bacteria, however absent in mammals. This pathway is vital for bacteria due to its critical role in cell wall biosynthesis. One of the essential enzymes of this pathway is dihydrodipicolinate synthase (DHDPS), considered to be crucial for the bacterial survival. In view of its importance, the development and prediction of potent inhibitors against DHDPS may be valuable to design effective drugs against bacteria, in general.