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Durai, Prasannavenkatesh,Batool, Maria,Shah, Masaud,Choi, Sangdun Nature Publishing Group 2015 Experimental and molecular medicine Vol.47 No.8
<P>Middle East respiratory syndrome coronavirus (MERS-CoV) causes high fever, cough, acute respiratory tract infection and multiorgan dysfunction that may eventually lead to the death of the infected individuals. MERS-CoV is thought to be transmitted to humans through dromedary camels. The occurrence of the virus was first reported in the Middle East and it subsequently spread to several parts of the world. Since 2012, about 1368 infections, including ~487 deaths, have been reported worldwide. Notably, the recent human-to-human ‘superspreading' of MERS-CoV in hospitals in South Korea has raised a major global health concern. The fatality rate in MERS-CoV infection is four times higher compared with that of the closely related severe acute respiratory syndrome coronavirus infection. Currently, no drug has been clinically approved to control MERS-CoV infection. In this study, we highlight the potential drug targets that can be used to develop anti-MERS-CoV therapeutics.</P>
Durai, Prasannavenkatesh,Govindaraj, Rajiv Gandhi,Choi, Sangdun Published by Blackwell Pub. on behalf of the Feder 2013 The FEBS journal Vol.280 No.23
<P>Proinflammatory responses by Toll‐like receptors (TLRs) to malaria infection are considered to be a significant factor in suppressing pathogen growth and in disease control. The key protozoan parasite <I>Plasmodium falciparum</I> causes malaria through glycosylphosphatidylinositols (GPIs), which induce the host immune response mainly via TLR2 signalling. Experimental studies have suggested that malarial GPIs from <I>P. falciparum</I> are recognized by the TLR2 subfamily. However, the interaction site and their involvement in the activation mechanism are still unknown. A better understanding of the detailed structure of the TLR–GPI interaction is important for the design of more effective anti‐malarial therapeutics. We used a molecular docking method to predict the binding regions of malarial GPIs with the TLR2 subfamily members. We also employed molecular dynamics simulations and principal component analysis to understand ligand‐induced conformational changes of the TLR2 subfamily. We observed the expected structural changes upon ligand binding, and significant movements were found in loop regions located in the ligand‐binding site of the TLR2 subfamily. We further propose that the binding modes of malarial GPIs are similar to lipopeptides, and that the lipid portions of the ligands could play an essential role in selective dimerization of the TLR2 subfamily.</P>
( Prasannavenkatesh Durai ),( Yeongjoon Lee ),( Jieun Kim ),( Dasom Jeon ),( Yangmee Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.5
Papiliocin, isolated from the swallowtail butterfly (Papilio xuthus), is an antimicrobial peptide with high selectivity against gram-negative bacteria. We previously showed that the N-terminal helix of papiliocin (PapN) plays a key role in the antibacterial and anti-inflammatory activity of papiliocin. In this study, we measured the selectivity of PapN against multidrug-resistant gram-negative bacteria, as well as its anti-inflammatory activity. Interactions between Trp2 of PapN and lipopolysaccharide (LPS), which is a major component of the outer membrane of gram-negative bacteria, were studied using the Trp fluorescence blue shift and quenching in LPS micelles. Furthermore, using circular dichroism, we investigated the interactions between PapN and LPS, showing that LPS plays critical roles in peptide folding. Our results demonstrated that Trp2 in PapN was buried deep in the negatively charged LPS, and Trp2 induced the α-helical structure of PapN. Importantly, docking studies determined that predominant electrostatic interactions of positively charged arginine residues in PapN with phosphate head groups of LPS were key factors for binding. Similarly, hydrophobic interactions by aromatic residues of PapN with fatty acid chains in LPS were also significant for binding. These results may facilitate the development of peptide antibiotics with anti-inflammatory activity.
Lee, Yeongjoon,Kwak, Chulhee,Jeong, Ki-Woong,Durai, Prasannavenkatesh,Ryu, Kyoung-Seok,Kim, Eun-Hee,Cheong, Chaejoon,Ahn, Hee-Chul,Kim, Hak Jun,Kim, Yangmee American Chemical Society 2018 Biochemistry Vol.57 No.26
<P>Cold-shock proteins (Csps) are expressed at lower-than-optimum temperatures, and they function as RNA chaperones; however, no structural studies on psychrophilic Csps have been reported. Here, we aimed to investigate the structure and dynamics of the Csp of psychrophile <I>Colwellia psychrerythraea</I> 34H, (<I>Cp</I>-Csp). Although <I>Cp</I>-Csp shares sequence homology, common folding patterns, and motifs, including a five β-stranded barrel, with its thermophilic counterparts, its thermostability (37 °C) was markedly lower than those of other Csps. <I>Cp</I>-Csp binds heptathymidine with an affinity of 10<SUP>-7</SUP> M, thereby increasing its thermostability to 50 °C. Nuclear magnetic resonance spectroscopic analysis of the <I>Cp</I>-Csp structure and backbone dynamics revealed a flexible structure with only one salt bridge and 10 residues in the hydrophobic cavity. Notably, <I>Cp</I>-Csp contains Tyr51 instead of the conserved Phe in the hydrophobic core, and its phenolic hydroxyl group projects toward the surface. The Y51F mutation increased the stability of hydrophobic packing and may have allowed for the formation of a K3-E21 salt bridge, thereby increasing its thermostability to 43 °C. <I>Cp</I>-Csp exhibited conformational exchanges in its ribonucleoprotein motifs 1 and 2 (754 and 642 s<SUP>-1</SUP>), and heptathymidine binding markedly decreased these motions. <I>Cp-</I>Csp lacks salt bridges and has longer flexible loops and a less compact hydrophobic cavity resulting from Tyr51 compared to mesophilic and thermophilic Csps. These might explain the low thermostability of <I>Cp</I>-Csp. The conformational flexibility of <I>Cp-</I>Csp facilitates its accommodation of nucleic acids at low temperatures in polar oceans and its function as an RNA chaperone for cold adaptation.</P> [FIG OMISSION]</BR>