The Role of Cysteine Residues in Catalysis of Phosphoenolpyruvate Carboxykinase from Mycobacterium tuberculosis
نویسندگان
چکیده
Mycobacterium tuberculosis (MTb), the causative agent of tuberculosis, can persist in macrophages for decades, maintaining its basic metabolic activities. Phosphoenolpyruvate carboxykinase (Pck; EC 4.1.1.32) is a key player in central carbon metabolism regulation. In replicating MTb, Pck is associated with gluconeogenesis, but in non-replicating MTb, it also catalyzes the reverse anaplerotic reaction. Here, we explored the role of selected cysteine residues in function of MTb Pck under different redox conditions. Using mass spectrometry analysis we confirmed formation of S-S bridge between cysteines C391 and C397 localized in the C-terminal subdomain. Molecular dynamics simulations of C391-C397 bridged model indicated local conformation changes needed for formation of the disulfide. Further, we used circular dichroism and Raman spectroscopy to analyze the influence of C391 and C397 mutations on Pck secondary and tertiary structures, and on enzyme activity and specificity. We demonstrate the regulatory role of C391 and C397 that form the S-S bridge and in the reduced form stabilize Pck tertiary structure and conformation for gluconeogenic and anaplerotic reactions.
منابع مشابه
Structural and Functional Studies of Phosphoenolpyruvate Carboxykinase from Mycobacterium tuberculosis
Tuberculosis, the second leading infectious disease killer after HIV, remains a top public health priority. The causative agent of tuberculosis, Mycobacterium tuberculosis (Mtb), which can cause both acute and clinically latent infections, reprograms metabolism in response to the host niche. Phosphoenolpyruvate carboxykinase (Pck) is the enzyme at the center of the phosphoenolpyruvate-pyruvate-...
متن کاملModulation of Central Carbon Metabolism by Acetylation of Isocitrate Lyase in Mycobacterium tuberculosis
Several enzymes involved in central carbon metabolism such as isocitrate lyase and phosphoenolpyruvate carboxykinase are key determinants of pathogenesis of Mycobacterium tuberculosis (M. tb). In this study, we found that lysine acetylation plays an important role in the modulation of central carbon metabolism in M. tb. Mutant of M. tb defective in sirtuin deacetylase exhibited improved growth ...
متن کاملActivation and inactivation of phosphoenolpyruvate carboxykinase by ferrous ions.
Phosphoenolpyruvate carboxykinase from rat liver cytosol is activated by Fe2+ ions in either direction of catalysis. Preincubation of the purified enzyme with Fe2+ ions causes a time-dependent irreversible loss of activity; this is not seen with unpurified enzyme. Purified enzyme can be protected from inactivation by Fe2+ ions by partially purified protein fractions from liver (ferroactivator f...
متن کاملMptpB, a virulence factor from Mycobacterium tuberculosis, exhibits triple-specificity phosphatase activity.
Bacterial pathogens have developed sophisticated mechanisms of evading the immune system to survive in infected host cells. Central to the pathogenesis of Mycobacterium tuberculosis is the arrest of phagosome maturation, partly through interference with PtdIns signalling. The protein phosphatase MptpB is an essential secreted virulence factor in M. tuberculosis. A combination of bioinformatics ...
متن کاملFunction and Structure of a Prokaryotic Formylglycine-generating Enzyme*S⃞
Type I sulfatases require an unusual co- or post-translational modification for their activity in hydrolyzing sulfate esters. In eukaryotic sulfatases, an active site cysteine residue is oxidized to the aldehyde-containing C(alpha)-formylglycine residue by the formylglycine-generating enzyme (FGE). The machinery responsible for sulfatase activation is poorly understood in prokaryotes. Here we d...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 12 شماره
صفحات -
تاریخ انتشار 2017