Nanosecond dynamics of influenza A/M2TM and an amantadine resistant mutant probed by time-dependent red shifts of a native tryptophan

Vikas Nanda, Lidia Cristian, Dmitri Toptygin, Ludwig Brand, William F. DeGrado

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Proteins involved in functions such as electron transfer or ion transport must be capable of stabilizing transient charged species on time scales ranging from picoseconds to microseconds. We study the influenza A M2 proton channel, containing a tryptophan residue that serves as an essential part of the proton conduction pathway. We induce a transition dipole in tryptophan by photoexcitation, and then probe the dielectric stabilization of its excited state. The magnitude of the stabilization over this time regime was larger than that generally found for tryptophan in membrane or protein environments. M2 achieves a water-like stabilization over a 25 ns time scale, slower than that of bulk water, but sufficiently rapid to contribute to stabilization of charge as protons diffuse through the channel. These measurements should stimulate future MD studies to clarify the role of sidechain versus non-bulk water in defining the process of relaxation.

Original languageEnglish (US)
Pages (from-to)73-79
Number of pages7
JournalChemical Physics
Volume422
DOIs
StatePublished - Jan 1 2013

Fingerprint

influenza
Amantadine
tryptophan
Tryptophan
red shift
Stabilization
stabilization
Protons
protons
Water
water
proteins
Photoexcitation
photoexcitation
Excited states
electron transfer
Proteins
Ions
dipoles
membranes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Keywords

  • Charge stabilization
  • Dielectric relaxation
  • M2 proton channel
  • Nanosecond dynamics

Cite this

Nanda, Vikas ; Cristian, Lidia ; Toptygin, Dmitri ; Brand, Ludwig ; DeGrado, William F. / Nanosecond dynamics of influenza A/M2TM and an amantadine resistant mutant probed by time-dependent red shifts of a native tryptophan. In: Chemical Physics. 2013 ; Vol. 422. pp. 73-79.
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Nanosecond dynamics of influenza A/M2TM and an amantadine resistant mutant probed by time-dependent red shifts of a native tryptophan. / Nanda, Vikas; Cristian, Lidia; Toptygin, Dmitri; Brand, Ludwig; DeGrado, William F.

In: Chemical Physics, Vol. 422, 01.01.2013, p. 73-79.

Research output: Contribution to journalArticle

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