RESUMO
Fertilin, a heterodimeric sperm surface protein, first identified in guinea pig, has been shown to play an important role in sperm-egg interactions. We report here the complementary DNA and deduced amino acid sequence of human fertilin beta. The human fertilin beta shares significant sequence homology with mouse, guinea pig and monkey fertilin beta and also exhibits similar structural organization. Of particular interest, the mature guinea pig fertilin beta contains an amino-terminal 90 amino acid disintegrin domain. It has been suggested that the integrin recognition sequence (TDE) of the guinea pig fertilin beta disintegrin domain mediates sperm-egg binding. The amino acid sequence at this position in human fertilin beta differs from the mouse, guinea pig and monkey sequence (mouse-QDE; human-FEE; monkey-FDE).
Assuntos
Glicoproteínas de Membrana/biossíntese , Metaloendopeptidases/biossíntese , Testículo/metabolismo , Proteínas ADAM , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Encéfalo/metabolismo , Clonagem Molecular , DNA Complementar , Desintegrinas , Feminino , Fertilinas , Biblioteca Gênica , Cobaias , Haplorrinos , Humanos , Fígado/metabolismo , Masculino , Glicoproteínas de Membrana/química , Metaloendopeptidases/química , Camundongos , Dados de Sequência Molecular , Ovário/metabolismo , Peptídeos/química , Reação em Cadeia da Polimerase , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Homologia de Sequência de Aminoácidos , Interações Espermatozoide-Óvulo , Espermatozoides/fisiologiaRESUMO
Antistasin, a 15-kDa anticoagulant protein isolated from the salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of factor Xa in the blood coagulation cascade. Antistasin possesses a twofold internal homology between the N- and C-terminal halves of the molecule, suggesting a gene duplication event in the evolution of the antistasin gene. This structural feature also suggests that either or both halves of the protein may possess biological activity if expressed as separate domains. Because the N-terminal domain contains a factor Xa P1-reactive site, we chose to express this domain in an insect cell baculovirus expression system. Characterization of this recombinant half antistasin molecule reveals that the N-terminal domain inhibits factor Xa in vitro, with a K(i) of 1.7 nM.
