CGEMA and VGAP: a Colour Graphics Editor for Multiple Alignment using a Variable GAP penalty. Application to the muscarinic acetylcholine receptor

Summary Today, more than 40 protein amino acid (AA) sequences of membrane receptors coupled to guanine nucleotide binding proteins (G-proteins) are available. For those working in the field of medicinal chemistry, these sequences present a new type of information that should be taken into consideration. To make maximal use of sequence data it is essential to be able to compare different protein sequences in a similar way to that used for small molecules. A prerequisite, however, is the availability of a processing environment that enables one to handle sequences in an easy way, both by hand and by computer. In order to meet these ends, the package CGEMA (Colour Graphics Editor for Multiple Alignment) was developed in our laboratory. The programme uses a user-definable colour coding for the different AAs. Sequences can be aligned by hand or by computer, using VGAP, and both approaches can be combined. VGAP is a novel in-house written alignment programme with a variable gap penalty that also handles consecutive alignments using one sequence as a probe. In addition, secondary structure prediction tools are available.From the 20 protein sequences, available for the muscarinic acetylcholine receptor, 13 different sequences were selected, covering the subtypes m1 to m5. By comparing the sequences, two major groups are revealed that correspond to those found by considering the transducing system coupled to the various receptor subtypes. Different parts of the protein sequences are identified as characterizing the subtype and binding the ligands, respectively.     

Die Verwendung des elektrischen Stromes als W?rmequelle

Ohne Zusammenfassung     

Fuzzy cardinality and the modeling of imprecise quantification

The concept of cardinality of a fuzzy set has received attention from several researchers and has been defined in several apparently independent manners. A systematic investigation of this notion is performed which unifies and improves previous attempts. The cardinality of a fuzzy set, viewed as a fuzzy integer, is related to scalar cardinality indices. The closely related question of the probability of a fuzzy event is dealt with. Lastly, the usefulness of fuzzy cardinality for meaning representation of statements or queries involving fuzzy linguistic quantifiers is emphasized.     

Etude du mécanisme de perte d'ethylène (propène) des N-ethyl (propyl) bromo-1,2,4-triazoles

C-bromo-1,2,4-trizole is generated in three different tautomeric forms by ethylene elimination from the N-ethyl compounds and these toutomes are shown to retain their structure prior to further fragmentation. The analysis of mass analysed ion kinetic energy and collision incuded dissociation spectra confrrms that ethylene loss proceeds by a tw-step mechanism with a five- (or four-) centred hydrogen transfer. The results show also that the 3- and 5-bromotriazole structures only are responsible for the mass spectrum of the parent heterocycle. Similar data are dicussed for the loss of propene from N-propylbromotriazoles.     

New intramolecular exciplexes between polynuclear aromatic hydrocarbons and head-to-head vs head-to-tail photodimerization of mesosubstituted anthracenes.

New dissymetrical non conjugated bichromophores linked by an oxygenated chain: (9-anthrylmethyloxymethyl)arenes[arenes:benzene(I_a),2-naphthalene(I_b),9-phenanthrene (I_c) and 1-pyrene (I_d) and (9-phenanthrylmethyloxymethyl)-1-pyrene (II)] have been prepared. I_c–d and II exhibit intramolecular exciplex fluorescence in methylcyclohexane at room temperature. Intramolecular photoadducts were not found but I_a–d yield a mixture of head-to-head and head-to-tail anthracenic photodimers.     

Alkylation de la dimethyl-5 5′ isoxazolidinone-3 en catalyse par transfert de phase

Alkylation by phase transfert catalysis of ambidents anions of the N-C-0 type, leads to a mixture of N and O substitution. Isomers per cent are 20% for O alkylation and 80% for N alkylation when primary halides are used. With secondary halides, these figures are 35% and 65%. In both cases the overall yield ranges around 60%.