Structural characterization of the HSP70 interaction domain of the hepatitis C viral protein NS5A

Abstract

We previously identified the NS5A/HSP70 binding site to be a hairpin moiety at C-terminus of NS5A domain I and showed a corresponding cyclized polyarginine-tagged synthetic peptide (HCV4) significantly blocks virus production. Here, sequence comparison confirmed five residues to be conserved. Based on NS5A domain I crystal structure, Phe171, Val173, and Tyr178 were predicted to form the binding interface. Substitution of Phe171 and Val173 with more hydrophobic unusual amino acids improved peptide antiviral activity and HSP70 binding, while similar substitutions at Tyr178 had a negative effect. Substitution of non-conserved residues with arginines maintained antiviral activity and HSP70 binding and dispensed with polyarginine tag for cellular entry. Peptide cyclization improved antiviral activity and HSP70 binding. The cyclic retro-inverso analog displayed the best antiviral properties. FTIR spectroscopy confirmed a secondary structure consisting of an N-terminal beta-sheet followed by a turn and a C-terminal beta-sheet. These peptides constitute a new class of anti-HCV compounds.

Allosteric heat shock protein 70 inhibitors block hepatitis C virus assembly

“…2B). The previously reported HCV4 peptide (IC 50 = 452 pM), which inhibits viral translation, was used as a positive control [12,27]. To confirm the antiviral activity of AHIs, the wild-type virus was utilised in intracellular infectious virus production assays followed by Western analyses to measure the levels of viral proteins.…”

Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development

“…Virus entry RNA virus: CAV-9, 186 EV-A71, 188 DENV, 110,189 JEV, 191 ZIKV 190,197 DNA virus: SV40, 234 AdV, 237 HSV, 241 polyomavirus 254 RT virus: HTLV-1, 258,259 HIV-1 260 Virus replication RNA virus: MuV, 201 CDV, 203,204 HCV, 206 RSV, 209 EBOV, 212,213 Influenza 217 Virus gene expression RNA virus: Coxsackievirus B3, 218 EV-A71, 219 Influenza A [222][223][224][225][226] DNA virus: Polyomavirus, JCV, HCMV, 245,[246][247][248][249] Assembly RNA virus: Reovirus, 227 Poliovirus, 228 Coxsackievirus B1, 228 Influenza 229 DNA virus: Polyomavirus 254 Virus release RNA virus: HCV 232,233 Cellular transformation DNA virus: SV40, [264][265][266][267]…”

“…231 Silencing of Hsp70 decreases viral protein expression, but the virus protein level is not affected. 232,233 Instead, interfering Hsc70 reduces extracellular virion production. 232,233 Moreover, Hsc70 is embedded in the viral capsid.…”

Assessment of in vitro bioactivities of Pis v 1 (2S albumin) and Pis v 2.0101 (11S globulin) proteins derived from pistachio (Pistacia vera L.)

“…Recently, many viral diseases were treated with a combination of synthetic drugs which improve sustained virological response, but also produce adverse side effects including anemia and gastrointestinal symptoms [14]. In addition, antimicrobial proteins can exhibit antitumor and antiviral effects [27].…”

“…Adsorbed peptide supports the cell from the fusion glycoprotein of the virus and it is directly due to the fundamental peptide; however, small peptides may exhibit no antiviral activity because of their conformational instability [8]. In another study using FTIR spectroscopy, a secondary structure consisting of an N-terminal beta-sheet along with a turn and C-terminal beta-sheet was introduced as a new class of anti-HCV compounds [14].…”