Discovery of Spiro-Piperidine Inhibitors and Their Modulation of the Dynamics of the M2 Proton Channel from Influenza A Virus

Wang, Junyang; Cady, Sarah D.; Balannik, Victoria; Pinto, Lawrence H.; DeGrado, William F.; Hong, Mei

doi:10.1021/ja900063s

Cited by 87 publications

(92 citation statements)

References 54 publications

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“…87 that a variety of apolar substituents can replace the adamantyl substituent, and that a cationic primary ammonium group is optimal for high-affinity binding, as tertiary amines, alcohols, and other neutral groups tend to have lower affinity (secondary amines can be tolerated in some cases). 111 The effectiveness of primary amines suggested that the charged amine (ammonium) group might mimic hydronium ions, formed as protons percolate through the outer pore to His37. Indeed, MD simulations of amantadine in the channel showed that, on average, its ammonium group was hydrated by four water molecules in a square planar array, and this hydrate was further stabilized by hydrogen-bonding to four carbonyl groups from Ala30.…”

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confidence: 99%

Structural basis for proton conduction and inhibition by the influenza M2 protein

2012

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The influenza M2 protein forms an acid-activated and drug-sensitive proton channel in the virus envelope that is important for the virus lifecycle. The functional properties and high-resolution structures of this proton channel have been extensively studied to understand the mechanisms of proton conduction and drug inhibition. We review biochemical and electrophysiological studies of M2 and discuss how high-resolution structures have transformed our understanding of this proton channel. Comparison of structures obtained in different membrane-mimetic solvents and under different pH using X-ray crystallography, solution NMR, and solid-state NMR spectroscopy revealed how the M2 structure depends on the environment and showed that the pharmacologically relevant drug-binding site lies in the transmembrane (TM) pore. Competing models of proton conduction have been evaluated using biochemical experiments, high-resolution structural methods, and computational modeling. These results are converging to a model in which a histidine residue in the TM domain mediates proton relay with water, aided by microsecond conformational dynamics of the imidazole ring. These mechanistic insights are guiding the design of new inhibitors that target drug-resistant M2 variants and may be relevant for other proton channels.

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Structural basis for proton conduction and inhibition by the influenza M2 protein

2012

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“…Trp41 acts in concert with His37 as a "gate," helping to define the rate of proton flux and to kinetically trap protons within an acidified virus (16)(17)(18). Recent studies have shown that valine 27 at the entrance of the pore may act as a secondary gate of the A/M2 channel (17-19).M2 is the target of the adamantane-containing antiinfluenza drugs as well as related hydrophobic amine-containing structures (3,4,(20)(21)(22)(23). Structures of the A/M2 TM domain in complex with amantadine have been determined by X-ray crystallography (17) and solid-state NMR (24).…”

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confidence: 99%

“…M2 is the target of the adamantane-containing antiinfluenza drugs as well as related hydrophobic amine-containing structures (3,4,(20)(21)(22)(23). Structures of the A/M2 TM domain in complex with amantadine have been determined by X-ray crystallography (17) and solid-state NMR (24).…”

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Proton and cation transport activity of the M2 proton channel from influenza A virus

Leiding

Wang²,

Martinsson

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The M2 protein is a small, single-span transmembrane (TM) protein from the influenza A virus. This virus enters cells via endosomes; as the endosomes mature and become more acidic M2 facilitates proton transport into the viral interior, thereby disrupting matrix protein/RNA interactions required for infectivity. A mystery has been how protons can accumulate in the viral interior without developing a large electrical potential that impedes further inward proton translocation. Progress in addressing this question has been limited by the availability of robust methods of unidirectional insertion of the protein into virus-like vesicles. Using an optimized procedure for reconstitution, we show that M2 has antiporter-like activity, facilitating K þ or Na þ efflux when protons flow down a concentration gradient into the vesicles. Cation efflux is very small except under conditions mimicking those encountered by the endosomally entrapped virus, in which protons are flowing through the channel. This proton/cation exchange function is consistent with the known high proton selectivity of the channel. Thus, M2 acts as a proton uniporter that occasionally allows K þ to flow to maintain electrical neutrality. Remarkably, as the pH inside M2-containing vesicles (pH in ) decreases, the proton channel activity of M2 is inhibited, but its cation transport activity is activated. This reciprocal inhibition of proton flux and activation of cation flux with decreasing pH in first allows accumulation of protons in the early stages of acidification, then trapping of protons within the virus when low pH in is achieved.antiporter | liposomes | M2 channel | protons | ion channel T he influenza A virus M2 protein is a tetrameric integral membrane protein containing a short N-terminal extracellular domain, a transmembrane (TM) helix, and a 54-residue cytoplasmic tail (1, 2). Four M2 TM domains associate into a highly selective proton channel (3, 4) whose activity is essential for viral replication (5, 6). Influenza virus enters cells via the endosomal pathway, and the M2 protein functions to equilibrate the pH of the virus interior with that of the acidic endosome. The lowering of the pH within the virus leads to disruption of the interactions between the viral ribonucleoprotein (RNP) complex and the M1 protein (5), an important step in viral uncoating (7). Additionally, for some subtypes of influenza A virus, the M2 proton channel activity helps maintain a neutral pH in the lumen of the trans-Golgi network to prevent premature triggering of the hemagglutinin to the low-pH form (8-11). A long-standing question has been how M2 can conduct a substantial number of protons into the very small-volume interior of the virus without developing a substantial electrical gradient. Diffusion of a few protons down their concentration gradient from the acid environment of the endosome into the viral interior would result in an electrical gradient that would abruptly halt further proton flow and thereby prevent acidification of the viral interior. Here we...

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“…Based on non-adamantane compound 6 (Figure 3), Wang et al [62] have been searching for new classes of M2 inhibitors. With a structure activity relation, the spiro-piperidine compound 9 ( Figure 3) was found as the most active with low IC50 of 0.92±0.11 µM.…”

Section: Molecular Dynamic Stimulationmentioning

confidence: 99%

Computational analysis in Influenza virus

Chavan

Bapat²,

Patil³

et al. 2017

Receptor Clin Invest

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Influenza viruses are major human pathogens accountable for respiratory diseases affecting millions of people worldwide and characterized by high morbidity and significant mortality. Influenza infections can be controlled by vaccination and antiviral drugs. However, vaccines need yearly updating and give limited protection. In addition, the currently available drugs suffer from the rapid and extensive emergence of drug resistance. All this highlights the urgent need for developing new antiviral strategies with novel mechanisms of action and with reduced drug resistance potential. Recent advances in the understanding of Influenza virus replication have discovered a number of cellular drug targets that counteract viral drug resistance. With expanded bioinformatics' knowledge on computational modeling and molecular dynamic stimulations, novel small molecule inhibitors of herbal/ayurvedic origin are being explored due to their non-toxicity and affordability. Using in-silico techniques the structural details and information of influenza protein have been studied to identify the potential drugs for inhibition. Further, we have discussed the various computational studies carried out on major protein/targets of Influenza which could provide new clues for a newer class of antiviral (ayurvedic) drugs. In the years to come ahead, the influenza treatment will go through major changes, with advancing our knowledge of pathogenesis as new methods becoming clinically validated.

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Discovery of Spiro-Piperidine Inhibitors and Their Modulation of the Dynamics of the M2 Proton Channel from Influenza A Virus

Cited by 87 publications

References 54 publications

Structural basis for proton conduction and inhibition by the influenza M2 protein

Structural basis for proton conduction and inhibition by the influenza M2 protein

Proton and cation transport activity of the M2 proton channel from influenza A virus

Computational analysis in Influenza virus

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