4978 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 20
Brief Articles
Sch em e 1a
(4) (a) Salom, D.; Hill, B. R.; Lear, J . D.; DeGrado, W. F. pH-
dependent tetramerization and amantadine binding of the
transmembrane helix of M2 from the influenza A virus. Bio-
chemistry 2000, 39, 14160-14170. (b) Cristian, L.; Lear, J . D.;
DeGrado, W. F. Use of thiol-disulfide equilibria to measure the
energetics of assembly of transmembrane helices in phospholipid
bilayers. Proc. Natl. Acad. Sci. U.S.A. 2003, 100, 14772-14777.
(5) Duff, K. C.; Kelly, S. M.; Price, N. C.; Bradshaw, J . P. The
secondary structure of influenza A M2 transmembrane domain.
A circular dichroism study. FEBS Lett. 1992, 311, 256-258.
(6) Kukol, A.; Adams, P. D.; Rice, L. M.; Brunger, A. T.; Arkin, I. T.
Experimentally based orientational refinement of membrane
protein models: a structure for the influenza A M2 H+ channel.
J . Mol. Biol. 1999, 286, 951-962.
(7) (a) Wang, J .; Kim, S.; Kovacs, F.; Cross, T. A. Structure of the
transmembrane region of the M2 protein H+ channel. Protein
Sci. 2001, 10, 2241-2250. (b) Nishimura, K.; Kims, S.; Zhang,
L.; Cross, T. A. The closed state of a H+ channel helical bundle
combining precise orientational and distance restraints from
solid state NMR. Biochemistry 2002 41, 13170-13177. (c) Tian,
C.; Gao, P. F.; Pinto, L. H.; Lamb, R. A.; Cross, T. A. Initial
structural and dynamic characterization of the M2 protein
transmembrane and amphipathic helices in lipid bilayers.
Protein Sci. 2003, 12, 2597-2605.
a
Reagents and conditions: (a) KMnO4, KOH, 3 h, 60 °C (yield
70%); (b) TBAHSO4, NaHCO3, CH3I, acetone, 48 h, room temp
(99%); (c) DAST, CH2Cl2, 3 h, -80 °C f 25 °C (48%); (d) NaOH,
MeOH, THF, H2O, 12 h, room temp (85%); (e) DPPA, TEA, 45 min,
reflux, then BnOH, benzene, 72 h, reflux (quantitative); (f) H2,
10% Pd/C, AcOH, 50 psi, 6 h, room temp (84%).
(8) Forrest, L. R.; Kukol, A.; Arkin, I. T.; Tieleman, D. P.; Sansom,
M. S. P. Exploring models of the influenza A M2 channel: MD
simulations in a phospholipid bilayer. Biophys. J . 2000, 78, 55-
69.
open new avenues for discovering how ion channel-
blocker interactions can be described.
(9) Pinto, L. H.; Dieckmann, G. R.; Gandhi, C. S.; Shaughnessy, M.
A.; Papworth, C. G.; Braman, J .; Lear, J . D.; Lamb, R. A.;
DeGrado, W. F. A functionally defined model for the M2 proton
channel of influenza A virus suggests a mechanism for its ion
selectivity. Proc. Natl. Acad. Sci. U.S.A. 1997, 94, 11301-11306.
(10) Gandhi, C. S.; Shuck, K.; Lear, J . D.; Dieckmann, G. R.;
DeGrado, W. F.; Lamb, R. A.; Pinto, L. H. Cu(II) inhibition of
the proton translocation machinery of the influenza A virus M2
protein. J . Biol. Chem. 1999, 274, 5474-5482.
Exp er im en ta l Section
The synthesis of F-Am 2 is illustrated in Scheme 1. Details
of the preparation of liposomes and proteoliposomes and the
1H NMR spectroscopy are reported in Supporting Information.
Ack n ow led gm en t. A.K. gratefully acknowledges
the Royal Society for the award of a travel grant to
perform NMR experiments in Cambridge.
(11) Stockman, B. J .; Dalvit, C. NMR screening techniques in drug
discovery and drug design. Prog. Nucl. Magn. Reson. Spectrosc.
2002, 41, 187-231.
(12) Mason, R. P.; Rhodes, D. G.; Herbette, L. G. Reevaluating
equilibrium and kinetic binding parameters for lipophilic drugs
based on a structural model for drug interaction with biological
membranes. J . Med. Chem. 1991, 34, 869-877.
(13) J asys, V. J .; Lombardo, F.; Appleton, T. A.; Bordner, J .; Ziliox,
M.; Volkmann, R. A. Preparation of fluoroadamantane acids and
amines: impact of bridgehead fluorine substitution on the
solution- and solid-state properties of functionalized adaman-
tanes. J . Am. Chem. Soc. 2000, 122, 466-473 and references
therein.
Su p p or tin g In for m a tion Ava ila ble: Experimental de-
tails. This material is available free of charge via the Internet
at http://pubs.acs.org.
Refer en ces
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past and present. Annu. Rev. Med. 2000, 51, 407-421. (b) Reid,
A. H.; Taubenberger, J . K. The origin of the 1918 pandemic
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(2) (a) Kolocouris, N.; Kolocouris, A.; Foscolos, G. B.; Fytas, G.;
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Padalko, E.; Neyts, J .; De Clercq, E. Are the 2-isomers of the
drug rimantadine active anti-influenza A agents? Antiviral
Chem. Chemother. 2003, 14, 153-164.
(14) Wang, C.; Takeuchi, K.; Pinto, L. H.; Lamb, R. A. Ion channel
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(15) Duff, K. C.; Ashley, R. H. The transmembrane domain of
influenza A M2 protein forms amantadine-sensitive proton
channels in planar lipid bilayers. Virology 1992, 190, 485-489.
(16) F-Am 2 has a pKa ≈ 9.5. See ref 13.
(17) Hansen, R. K.; Broadhurst, R. W.; Skelton, P. C.; Arkin, I. T.
Hydrogen/deuterium exchange of hydrophobic peptides in model
membranes by electrospray ionization mass spectrometry. J . Am.
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(3) Sakaguchi, T.; Tu, Q.; Pinto, L. H.; Lamb, R. A. The active
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