tetano
Editor, Senior Moderator
J Am Chem Soc. 2013 Sep 3. [Epub ahead of print]
Chemical Insight into the Emergence of Influenza Virus Strains That Are Resistant to Relenza.
Shidmoossavee FS, Watson JN, Bennet AJ.
Source
Department of Chemistry, Simon Fraser University , 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada.
Abstract
A reagent panel containing ten 4-substituted 4-nitrophenyl α-d-sialosides and a second panel of the corresponding sialic acid glycals were synthesized and used to probe the inhibition mechanism for two neuraminidases, the N2 enzyme from influenza type A virus and the enzyme from Micromonospora viridifaciens. For the viral enzyme the logarithm of the inhibition constant (Ki) correlated with neither the logarithm of the catalytic efficiency (kcat/Km) nor catalytic proficiency (kcat/Kmkun). These linear free energy relationship data support the notion that these inhibitors, which include the therapeutic agent Relenza, are not transition state mimics for the enzyme-catalyzed hydrolysis reaction. Moreover, for the influenza enzyme, a correlation (slope, 0.80 ? 0.08) is observed between the logarithms of the inhibition (Ki) and Michaelis (Km) constants. We conclude that the free energy for Relenza binding to the influenza enzyme mimics the enzyme-substrate interactions at the Michaelis complex. Thus, an influenza mutational response to a 4-substituted sialic acid glycal inhibitor can weaken the interactions between the inhibitor and the viral neuraminidase without a concomitant decrease in free energy of binding for the substrate at the enzyme-catalyzed hydrolysis transition state. The current findings make it clear that new structural motifs and/or substitution patterns need to be developed in the search for a bona fide influenza viral neuraminidase transition state analogue inhibitor.
PMID:
24001125
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24001125
Chemical Insight into the Emergence of Influenza Virus Strains That Are Resistant to Relenza.
Shidmoossavee FS, Watson JN, Bennet AJ.
Source
Department of Chemistry, Simon Fraser University , 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada.
Abstract
A reagent panel containing ten 4-substituted 4-nitrophenyl α-d-sialosides and a second panel of the corresponding sialic acid glycals were synthesized and used to probe the inhibition mechanism for two neuraminidases, the N2 enzyme from influenza type A virus and the enzyme from Micromonospora viridifaciens. For the viral enzyme the logarithm of the inhibition constant (Ki) correlated with neither the logarithm of the catalytic efficiency (kcat/Km) nor catalytic proficiency (kcat/Kmkun). These linear free energy relationship data support the notion that these inhibitors, which include the therapeutic agent Relenza, are not transition state mimics for the enzyme-catalyzed hydrolysis reaction. Moreover, for the influenza enzyme, a correlation (slope, 0.80 ? 0.08) is observed between the logarithms of the inhibition (Ki) and Michaelis (Km) constants. We conclude that the free energy for Relenza binding to the influenza enzyme mimics the enzyme-substrate interactions at the Michaelis complex. Thus, an influenza mutational response to a 4-substituted sialic acid glycal inhibitor can weaken the interactions between the inhibitor and the viral neuraminidase without a concomitant decrease in free energy of binding for the substrate at the enzyme-catalyzed hydrolysis transition state. The current findings make it clear that new structural motifs and/or substitution patterns need to be developed in the search for a bona fide influenza viral neuraminidase transition state analogue inhibitor.
PMID:
24001125
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24001125