Sandbox Reserved 428: Difference between revisions
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A unique hydrophobic pocket (viewable in <scene name='48/483885/Hydrophobic_pocket_denv-3mtase/3'>DENV-3 MTase Hydrophobic Surface Model</scene> and <scene name='48/483885/Hydrophobic_pocket_denv-2mtase/2'>DENV-2 MTase Hydrophobic Surface Model</scene>) was identified in this protein above the adenine base identified in West Nile Virus with conserved amino acids Phe-133, Ile-147, Gly-148, Glu-149, Arg-160, Arg 163, Val-164, and Leu-182. Phe-133 and Ile-147 are of particular interest because of their functionality in the binding cavity. Alanine mutations revealed various effects on the production and viral titer of DENV-3 MTase. Table below<ref>J Biol Chem. 2011 Feb 25;286(8):6233-40. Epub 2010 Dec 8. PMID:21147775 doi:10.1074/jbc.M110.179184</ref>, shows the various effects of Alanine mutations at selected sites. These transfectation experiments revealed that mutations at the N-7 (R160A, R160A) or 2’-O (F133A, L18A) methylation activities were significantly depreciated. Melting temperatures in the table indicate low mis-folding in the mutant MTases with respect to the wild type. These attributes confirm observations in WNV MTase; that the identified hydrophobic pocket is critical to Flavivirus cap methylations and replication within cell environments. Diminishment in these properties decrease the virus’s overall potency. Therefore selective inhibition of DENV-3 MTase at this unique binding cavity becomes a viable antiviral strategy. | A unique hydrophobic pocket (viewable in <scene name='48/483885/Hydrophobic_pocket_denv-3mtase/3'>DENV-3 MTase Hydrophobic Surface Model</scene> and <scene name='48/483885/Hydrophobic_pocket_denv-2mtase/2'>DENV-2 MTase Hydrophobic Surface Model</scene>) was identified in this protein above the adenine base identified in West Nile Virus with conserved amino acids Phe-133, Ile-147, Gly-148, Glu-149, Arg-160, Arg 163, Val-164, and Leu-182. Phe-133 and Ile-147 are of particular interest because of their functionality in the binding cavity. Alanine mutations revealed various effects on the production and viral titer of DENV-3 MTase. Table below<ref>J Biol Chem. 2011 Feb 25;286(8):6233-40. Epub 2010 Dec 8. PMID:21147775 doi:10.1074/jbc.M110.179184</ref>, shows the various effects of Alanine mutations at selected sites. These transfectation experiments revealed that mutations at the N-7 (R160A, R160A) or 2’-O (F133A, L18A) methylation activities were significantly depreciated. Melting temperatures in the table indicate low mis-folding in the mutant MTases with respect to the wild type. These attributes confirm observations in WNV MTase; that the identified hydrophobic pocket is critical to Flavivirus cap methylations and replication within cell environments. Diminishment in these properties decrease the virus’s overall potency. Therefore selective inhibition of DENV-3 MTase at this unique binding cavity becomes a viable antiviral strategy. | ||
Compounds were experimentally used to test for inhibitory strength and several key conclusions were made. SAH is non-selective and therefore inhibits eukaryotic, bacterial and viral DENV, WNV, human RNA, DNA, and histone MTases. Attachment of a benzyl ring increased selectivity for DENV MTase, however extending the aryl group by a length of one carbon reduced inhibition due to hydrophobic steric hindrance and flexibility causing bond attenuation. Meta-substitution on the benzyl moiety caused significant increase in inhibition compared to SAH. Larger bromine and iodine groups showed reduced inhibition suggesting further steric hindrance from bulky groups. The N6-substituted benzy ring with chloro functionality revealed rotation of Phe-133 to accommodate the bulky benzyl group, and strong cation-pi interaction between Arg-163 and the aryl-ring. | |||
