Studies on the functional significance of a C-terminal S-shaped motif in human arginase type I: Essentiality for cooperative effects

David García, Elena Uribe, Marcela Lobos, María S. Orellana, Nelson Carvajal

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

15 Citas (Scopus)

Resumen

The functional significance of a C-terminal S-shaped motif (residues 304-322) in human arginase I was explored by examining the kinetic properties of the R308A mutant and truncated species terminating in either Arg-308 or Ala-308. Replacement of Arg-308 with alanine, with or without truncation, yielded monomeric species. All mutants were kinetically indistinguishable from the wild-type enzyme at the optimum pH of 9.5. At the more physiological, pH 7.5, hyperbolic kinetics was observed for all the mutants, in contrast with the cooperative behavior exhibited by the wild-type species. In the presence of 2 mM guanidinium chloride (Gdn+), the single mutant R308A changed to a trimeric and kinetically cooperative form, whereas the other enzyme variants were not altered. The S-shaped motif is suggested as essential for the cooperative response of the enzyme to l-arginine at pH 7.5. Gdn+ is suggested to mimic the guanidine group of Arg-308 at the monomer-monomer interface.

Idioma originalInglés
Páginas (desde-hasta)16-20
Número de páginas5
PublicaciónArchives of Biochemistry and Biophysics
Volumen481
N.º1
DOI
EstadoPublicada - 1 ene 2009
Publicado de forma externa

Áreas temáticas de ASJC Scopus

  • Biofísica
  • Bioquímica
  • Biología molecular

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