S-nitrosylation of Mycobacterium tuberculosis tyrosine phosphatase A (PtpA) induces its structural instability.
Biochim Biophys Acta
; 1834(1): 191-6, 2013 Jan.
Article
em En
| MEDLINE
| ID: mdl-23102706
ABSTRACT
S-nitrosylation is associated with signal transduction and microbicidal activity of nitric oxide (NO). We have recently described the S-nitrosylation of Mycobacterium tuberculosis protein tyrosine phosphatase A, PtpA, an enzyme that plays an important role in mycobacteria survival inside macrophages. This post-translational modification decreases the activity of the enzyme upon modification of a single Cys residue, C53. The aim of the present work was the investigation of the effect of S-nitrosylation in PtpA kinetic parameters, thermal stability and structure. It was observed that the K(M) of nitrosylated PtpA was similar to its unmodified form, but the V(max) was significantly reduced. In contrast, treatment of PtpA C53A with GSNO, did not alter either K(M) or V(max). These results confirmed that PtpA S-nitrosylation occurs specifically in the non-catalytic C53 and that this modification does not affect substrate affinity. Using circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy techniques it was shown that PtpA S-nitrosylation decreased protein thermal stability and promoted a local effect in the surroundings of the C53 residue, which interfered in both protein stability and function.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
2_ODS3
/
3_ND
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Proteínas Tirosina Fosfatases
/
Mutação de Sentido Incorreto
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Mycobacterium tuberculosis
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2013
Tipo de documento:
Article