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7.
Mol Reprod Dev ; 51(2): 184-92, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9740326

RESUMO

Proacrosin, the zymogen form of the serine protease beta-acrosin, is thought to function as a secondary binding molecule between mammalian gametes during fertilization (Jansen et al., 1995: Int J Dev Biol 39, 501-510). The interaction involves strong ionic bonds between positively charged amino acids on proacrosin and negatively charged polysulphate groups on zona pellucida glycoproteins. In this investigation, we identified the basic residues on proacrosin that are important for this binding. Site-directed mutagenesis shows that two groups of amino acids comprising His47, Arg50, and Arg51 together with Arg250, Lys252, and Arg253 are crucial because their deletion or replacement severely reduces affinity for zona glycoproteins. Molecular models of proacrosin reveal that these residues are located along one face of the protein on two exposed surface loops that project over and around the catalytic site. These findings support the hypothesis that polysulphate binding sites on proacrosin are formed by a restricted number of basic amino acids on the surface of the protein, presenting a specific orientation that is complementary to negatively charged sulphate groups on zona glycoproteins. Identification and elucidation of the stereochemistry of these charged moieties will aid design of new kinds of nonsteroidal antifertility agents.


Assuntos
Acrosina/genética , Acrosina/metabolismo , Proteínas do Ovo/metabolismo , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Glicoproteínas de Membrana/metabolismo , Mutagênese Sítio-Dirigida , Receptores de Superfície Celular , Acrosina/química , Animais , Sítios de Ligação , Precursores Enzimáticos/química , Masculino , Modelos Moleculares , Conformação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Suínos , Glicoproteínas da Zona Pelúcida
8.
Biotechniques ; 24(6): 998-1001, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9631192

RESUMO

Here, we present a Microsoft Windows application that has been written to emulate a microplate reader. After scanning a standard 96-well microplate, color gradations in the slots can be analyzed quantitatively and be used for the estimation of enzyme kinetics, binding assays or concentration determination. In a test, series accuracy of the program was determined. We show that the returned optical densities correlated highly with the true concentrations (r > 0.97). Thus, the software is useful for a wide number of applications. Further, the program is easy to handle and is available free of charge.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Processamento de Imagem Assistida por Computador/métodos , Software , Ensaio de Imunoadsorção Enzimática/instrumentação , Processamento de Imagem Assistida por Computador/instrumentação , Reprodutibilidade dos Testes , Processamento de Sinais Assistido por Computador
10.
Biochim Biophys Acta ; 1336(3): 361-6, 1997 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-9367162

RESUMO

Glycosyltransferases play an important role in the synthesis of glycoproteins. Here we report the isolation of a brain cDNA coding for 89% of the porcine UDP-N-acetylglucosamine:alpha-6-D-mannoside-beta-1,2-N-acetylglucosaminy ltransferase II (EC 2.4.1.143) (GnTII). The cDNA was used for screening a genomic liver DNA library and isolation of a recombinant lambda FIX II phage containing the complete porcine GnTII gene and upstream and downstream sequences. The beta-1,2-N-acetylglucosaminyltransferase II gene harbours a single exon with an open reading frame of 1338 bp coding for a 446 amino acid protein with a calculated molecular mass of 51.1 kDa. The promoter of the GnTII gene is lacking a TATA-box and shows variable transcription start sites. In the 3'-untranslated region a polymorphic polyadenosine stretch was detected. The porcine GnTII gene contains four polyadenylation sites. PCR analysis of a porcine-rodent hybrid cell panel revealed the chromosomal location of the GnTII gene on SSC 1q23-q27. The mapping data of the cell panel were confirmed by fluorescence in situ hybridization (FISH) on metaphase chromosomes.


Assuntos
Encéfalo/enzimologia , Mapeamento Cromossômico , N-Acetilglucosaminiltransferases/biossíntese , N-Acetilglucosaminiltransferases/genética , Suínos/genética , Animais , Sequência de Bases , Clonagem de Organismos , Primers do DNA , Éxons , Dados de Sequência Molecular , N-Acetilglucosaminiltransferases/química , Fases de Leitura Aberta , Reação em Cadeia da Polimerase , Polimorfismo Genético , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Sequências Reguladoras de Ácido Nucleico
13.
Dtsch Tierarztl Wochenschr ; 103(10): 400-3, 1996 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-9035970

RESUMO

Proacrosin is a molecule that is located under the acrosomal cap and that acts as a secondary ligand after acrosome reaction. Proacrosin is thought to bind to ZP2 (zona pellucida receptor 2). The high affinity is based on the interaction of the zona pellucida glycoprotein's acidic sulphate groups with basic, positively charged amino acids of the proacrosin molecule. Proacrosin is a serine protease and is capable to lyse the zona pellucida locally. Our structural analysis of proacrosin shows, that the catalytic centre is surrounded by loops containing positively charged amino acids which create the binding domain. This review is intended to describe the results that lead to the elucidation of the biochemistry of proacrosin.


Assuntos
Acrosina/metabolismo , Acrossomo/metabolismo , Precursores Enzimáticos/metabolismo , Acrosina/química , Acrossomo/química , Animais , Proteínas do Ovo/química , Proteínas do Ovo/metabolismo , Precursores Enzimáticos/química , Masculino , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Zona Pelúcida/química , Zona Pelúcida/metabolismo , Glicoproteínas da Zona Pelúcida
14.
Dtsch Tierarztl Wochenschr ; 103(10): 414-6, 1996 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-9035973

RESUMO

The reproductive success in domestic animals is an important factor towards the economical production of livestock. Thus, a lot of energy has been spent on the amelioration of the reproduction by means of genetics but no considerable success was achieved since the additive genetic variance is low. This communication is supposed to elucidate its molecular biological basis in reproduction and furthermore, the article should point out the way in research how to improve reproductive parameters. We propose to characterize all sorts of genes and their gene products that are involved in reproduction. This is to realize a full understanding of the sperm egg interaction and to derive benefit from effects like heterosis.


Assuntos
Animais Domésticos/fisiologia , Cruzamento , Reprodução/genética , Interações Espermatozoide-Óvulo/genética , Animais , Animais Domésticos/genética , Feminino , Vigor Híbrido , Masculino
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