Binding of curcumin and its long chain derivatives to the activator binding domain of novel protein kinase C

Abstract

Protein Kinase C (PKC) is a family of serine/threonine kinases that play a central role in cellular signal transduction. The second messenger diacylglycerol having two long carbon chains acts as the endogenous ligand for the PKCs. Polyphenol curcumin, the active constituent of Curcuma longa is an anticancer agent and modulates PKC activity. To develop curcumin derivatives as effective PKC activators, we synthesized several long chain derivatives of curcumin, characterized their absorption and fluorescence properties and studied their interaction with the activator-binding second cysteinerich C1B subdomain of PKCδ, PKCε and PKCθ. Curcumin (1) and its C16 long chain analog (4) quenched the intrinsic fluorescence of PKCδC1B, PKCεC1B and PKCθC1B in a manner similar to that of PKC activator 12-O-tetradecanoylphorbol 13-acetate (TPA). The EC 50 s of the curcumin derivatives for fluorescence quenching varied in the range of 4-11 μM, whereas, EC 50 s for TPA varied in the range of 3-6 μM. Fluorescence emission maxima of 1 and 4 were blue shifted and the fluorescence anisotropy values were increased in the presence of the C1B domains similar to that shown by the fluorescent analog of TPA, sapintoxin-D, confirming that they were bound to the proteins. Molecular docking of 1 and 4 with novel PKC C1B revealed that both the molecules form hydrogen bonds with the protein residues. The present result shows that curcumin and its long chain derivatives bind to the C1B subdomain of novel PKCs and can be further modified structurally to improve its binding and activity.

The Molecular Basis for the Pharmacokinetics and Pharmacodynamics of Curcumin and Its Metabolites in Relation to Cancer

“…3 for the H-bond donating phenylic protons. In addition to most of the protein targets mentioned in the preceding section, histone deacetylase 8 (Bora-Tatar et al, 2009) and protein kinase C (PKC)d (Majhi et al, 2010;Mamidi et al, 2012) (section III.E.6) have been identified as cancer-pertinent proteins with which curcumin associates as a result of phenylic hydroxyl group-mediated H-bonding.…”

“…References used in Fig. 3: [1] (Yoo and Medina-Franco, 2011); [2] (Muthenna et al, 2009);[5] (Milacic et al, 2008); [9] (Ngo and Li, 2012); [10] ; [11] (Majhi et al, 2010); [12] (Mamidi et al, 2012); [13] (Das et al, 2011);[15] (Bustanji et al, 2009). The data set has been included in Supplemental Table 1. 230 distances between curcumin and several amino acid residues ($2.7 Å), indicating that the metal-diketone interaction is quite significant in the binding of curcumin to HIV-1 integrase.…”

“…2 and 3, which revealed that curcumin tends to adopt an entirely different configuration for each molecular target. For instance, curcumin bends only slightly and retains most of its planar structure when interacting with the minor groove of duplexed oligonucleotides (Zsila et al, 2004;Koonammackal et al, 232 2011), whereas it becomes entirely nonplanar and often rotates around the longitudinal axis when interacting with, e.g., the C1B domain of PKCu (Majhi et al, 2010;Das et al, 2011), PfATP6 (Ji and), aldose reductases (Muthenna et al, 2009;Katsori et al, 2011), and beta amyloid peptides (Ngo and Li, 2012). As a result, curcumin is able to associate with a plethora of biomolecules due to its structural adaptability, which is "exploited" to maximize the number of interatomic bonds between curcumin and its target.…”

“…By using isolated PKCd agonist-binding (C1B) domains, it was shown that curcumin quenched the intrinsic PKC (tryptophan) fluorescence at an IC 50 of 10.6 mM compared with an IC 50 of 5.1 mM of the prototypical PKC agonist TPA (Majhi et al, 2010). Molecular docking studies indicated that curcumin forms two H-bonds with the PKCd C1B domain: one between the phenylic hydroxyl group of curcumin and the Leu251 carbonyl moiety and the second between the phenylic oxygen of curcumin and the Gln257 amide group (Majhi et al, 2010). Molecular docking studies further revealed that curcumin also binds to PKCu through H-bonding between the phenylic hydroxyl group and Gly254 on the PKCu C1B domain (Das et al, 2011).…”

Molecular docking analysis of curcumin analogues as human neutrophil elastase inhibitors

“…A few other reports also supported that curcumin and its analogues could bind to various enzymes which includes human immunodefi Molecular docking analysis of curcumin analogues as human Molecular docking analysis of curcumin analogues as human Molecular docking analysis of curcumin analogues as human Molecular docking analysis of curcumin analogues as human neutrophil elastase inhibitors neutrophil elastase inhibitors neutrophil elastase inhibitors neutrophil elastase inhibitors ciency virus type-I protease (Sui et al, 1993), cyclooxygenase-1 (Selvam et al, 2005), DNA polymerase λ (Takeuchi et al, 2006), platelet-12-lipoxygenase (Jankun et al, 2006), cyclooxygenase-2 (Padhye et al, 2009), DNA methyl transferase-1 (Liu et al, 2009), xanthine oxidase (Shen andJi, 2009), dipeptydyl peptidase-4 (Istyastono, 2009), glycogen synthase kinase-3β (Bustanji et al, 2009), ribonuclease A (Sahoo et al, 2009), glyoxalase-I (Liu et al, 2010), protein kinase C (Majhi et al, 2010) and matrix metalloproteinases (Girija et al, 2010).…”