Control of catalysis in globin coupled adenylate cyclase by a globin-B domain.
Arch Biochem Biophys
; 579: 85-90, 2015 Aug 01.
Article
em En
| MEDLINE
| ID: mdl-26095616
ABSTRACT
The globin coupled heme containing adenylate cyclase from Leishmania major (HemAC-Lm) has two globin domains (globin-A and globin-B). Globin-B domain (210-360 amino acids) may guide the interaction between globin-A and adenylate cyclase domains for the regulation of catalysis. We investigated the role of globin-B domain in HemAC-Lm by constructing a series of mutants namely Δ209 (209 amino acids deleted), Δ360 (360 amino acids deleted), H161A, H311A and H311A-Δ209. Spectroscopic data suggest that the Δ209 and H311A-Δ209 proteins to be Fe(2+)-O2 form and apo form, respectively, indicating that His311 residue in the globin-B domain is crucial for heme binding in Δ209 protein. However, the H311A mutant is still of the Fe(2+)-O2 form whereas H161A mutant shows the apo form, indicating that only His161 residue in the globin-A domain is responsible for heme binding in full length enzyme. cAMP measurements suggest that the activities of Δ360 and Δ209 proteins were â¼10 and â¼1000 times lesser than full length enzyme, respectively, leading to the fact that globin-B domain inhibited catalysis rather than activation in absence of globin-A domain. These data suggest that the O2 bound globin-A domain in HemAC-Lm allows the best cooperation of the catalytic domain interactions to generate optimum cAMP.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Globinas
/
Adenilil Ciclases
/
Escherichia coli
/
Heme
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Índia