Article

The structure of PknB in complex with mitoxantrone, an ATP-competitive inhibitor, suggests a mode of protein kinase regulation in mycobacteria.

Unité de Biochimie Structurale and CNRS URA2185, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.
FEBS Letters (Impact Factor: 3.34). 06/2006; 580(13):3018-22. DOI: 10.1016/j.febslet.2006.04.046
Source: PubMed

ABSTRACT Mycobacterium tuberculosis PknB is an essential receptor-like protein kinase involved in cell growth control. Here, we demonstrate that mitoxantrone, an anthraquinone derivative used in cancer therapy, is a PknB inhibitor capable of preventing mycobacterial growth. The structure of the complex reveals that mitoxantrone partially occupies the adenine-binding pocket in PknB, providing a framework for the design of compounds with potential therapeutic applications. PknB crystallizes as a 'back-to-back' homodimer identical to those observed in other structures of PknB in complex with ATP analogs. This organization resembles that of the RNA-dependent protein kinase PKR, suggesting a mechanism for kinase activation in mycobacteria.

1 Follower
 · 
106 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tuberculosis continues to be a serious health problem worldwide. The disease continues to be underdiagnosed and not properly treated. In conditions that affect the immune system, such as multiple sclerosis (MS), latent tuberculosis may thrive and reactivate during the use of immunomodulatory and immunosuppressive drugs. Among the best treatment options for patients with latent or active tuberculosis who have MS are IFN-β, glatiramer acetate and mitoxantrone. Drugs leading to a reduced number and/or function of lymphocytes should be avoided or used with caution. Tuberculosis must always be investigated in patients with MS and treated with rigor.
    Expert Review of Neurotherapeutics 09/2014; 14(11). DOI:10.1586/14737175.2014.962517 · 2.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tuberculosis causes more than two million deaths per year. Faced with this global threat it is crucial to better understand the physiology of the causative organism, Mycobacterium Tuberculosis, in order to develop efficient therapeutic strategies. PKnB from Mycobacterium tuberculosis is a crucial receptor-like protein kinase involved in signal transduction. M. tuberculosis PKnB is a trans-membrane Ser/Thr protein kinase (STPK) highly conserved in Gram-positive bacteria and apparently essential for Mycobacterial viability. We have attempted with the help of virtual screening and docking approach to expound the extent of specificity of protein kinase B towards different classes of Thiadiazoles (an anti-tubercular agent). The selected Thiadiazoles were selected on the basis of the structural specificity to the enzyme towards its substrate and inhibitors. Total number of Thiadiazoles were 5000 in number with the minimum binding energy of -10.46 kcal/mol with 10 molecules showing hydrogen bonds with the active site residue. The protein kinase B peptide contains two types of structural elements (Valine 95, Arginine 97) and basic residue ring constituted of glycine rich residue. The structure of the protein-ligand complex reveals that Thiadiazoles partially occupies the adenine-binding pocket in PKnB, providing a framework for the design of compounds with potential therapeutic applications. The study provides hints for the future design of new derivatives with higher potency and specificity.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs). A similar number of two-component systems are also present, indicating that these two signal transduction mechanisms are both important in the adaptation of this bacterial pathogen to its environment. The M. tuberculosis phosphoproteome includes hundreds of Ser- and Thr-phosphorylated proteins that participate in all aspects of M. tuberculosis biology, supporting a critical role for the STPKs in regulating M. tuberculosis physiology. Nine of the STPKs are receptor type kinases, with an extracytoplasmic sensor domain and an intracellular kinase domain, indicating that these kinases transduce external signals. Two other STPKs are cytoplasmic and have regulatory domains that sense changes within the cell. Structural analysis of some of the STPKs has led to advances in our understanding of the mechanisms by which these STPKs are activated and regulated. Functional analysis has provided insights into the effects of phosphorylation on the activity of several proteins, but for most phosphoproteins the role of phosphorylation in regulating function is unknown. Major future challenges include characterizing the functional effects of phosphorylation for this large number of phosphoproteins, identifying the cognate STPKs for these phosphoproteins, and determining the signals that the STPKs sense. Ultimately, combining these STPK-regulated processes into larger, integrated regulatory networks will provide deeper insight into M. tuberculosis adaptive mechanisms that contribute to tuberculosis pathogenesis. Finally, the STPKs offer attractive targets for inhibitor development that may lead to new therapies for drug-susceptible and drug-resistant tuberculosis.
    10/2014; 2(5). DOI:10.1128/microbiolspec.MGM2-0006-2013

Preview

Download
2 Downloads
Available from