Synthesis and degradation of cAMP in Giardia lamblia: possible role and characterization of a nucleotidyl cyclase with a single cyclase homology domain.
Biochem J
; 474(23): 4001-4017, 2017 11 21.
Article
en En
| MEDLINE
| ID: mdl-29054977
Despite its importance in the regulation of growth and differentiation processes of a variety of organisms, the mechanism of synthesis and degradation of cAMP (cyclic AMP) has not yet been described in Giardia lamblia In this work, we measured significant quantities of cAMP in trophozoites of G. lamblia incubated in vitro and later detected how it increases during the first hours of encystation, and how it then returns to basal levels at 24â
h. Through an analysis of the genome of G. lamblia, we found sequences of three putative enzymes - one phosphodiesterase (gPDE) and two nucleotidyl cyclases (gNC1 and gNC2) - that should be responsible for the regulation of cAMP in G. lamblia Later, an RT-PCR assay confirmed that these three genes are expressed in trophozoites. The bioinformatic analysis indicated that gPDE is a transmembrane protein of 154â
kDa, with a single catalytic domain in the C-terminal end; gNC1 is predicted to be a transmembrane protein of 74â
kDa, with only one class III cyclase homology domain (CHD) at the C-terminal end; and gNC2 should be a transmembrane protein of 246â
kDa, with two class III CHDs. Finally, we cloned and enriched the catalytic domain of gNC1 (gNC1cd) from bacteria. After that, we confirmed that gNC1cd has adenylyl cyclase (AC) activity. This enzymatic activity depends on the presence of Mn2+ and Ca2+, but no significant activity was displayed in the presence of Mg2+ Additionally, the AC activity of gNC1cd is competitively inhibited with GTP, so it is highly possible that gNC1 has guanylyl cyclase activity as well.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Protozoarias
/
Adenilil Ciclasas
/
Giardia lamblia
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AMP Cíclico
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Hidrolasas Diéster Fosfóricas
/
Guanilato Ciclasa
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Biochem J
Año:
2017
Tipo del documento:
Article
País de afiliación:
Argentina
Pais de publicación:
Reino Unido