RESUMO
The polymerization reaction of rabbit muscle actin was completely inhibited by reaction of one amino acid side chain per protein monomer with 5-diazonium-(1H)[14C]tetrazole. A tryptic peptide fingerprint showed a single peptide labeled by the reagent. The peptide was isolated and the labeled amino acid identified by amino acid analysis as Tyr-53. This side chain is not accessible to the reagent in F-actin. The modification is compared to similar inhibitions by other reagents.
Assuntos
Actinas/metabolismo , Músculos/metabolismo , Actinas/isolamento & purificação , Aminoácidos/análise , Animais , Sítios de Ligação , Cristalização , Compostos de Diazônio , Etilmaleimida , Substâncias Macromoleculares , Fragmentos de Peptídeos/análise , Ligação Proteica , Coelhos , Espectrofotometria , Espectrofotometria Ultravioleta , Tetrazóis , TripsinaRESUMO
With the aid of tartryl-bis-epsilon-aminocaprylazide artificial dimers were produced from F actin from rabbit striated muscle. These derivatives will not polymerize by themselves but are able to copolymerize fully with native G actin. By modification of a single side chain per dimer, this copolymerization was completely inhibited. The dimers are able to activate subfragment 1 ATPase of myosin and bind to DNase I with inactivation of the enzyme in the same manner as native G actin. Within the dimer, one ADP is immobilized and will exchange against ATP extremely slowly. The dimers do not bind to the mushroom toxin phalloidin.