Fluorescence of variant-3 scorpion neurotoxin: multiple decay components and multiple decay trytophan conformers

Christopher Haydock, Salah S. Sedarous, Zeljko Bajzer, Franklyn G. Prendergast

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The fluorescence intensity decay of variant-3 scorpion nuerotoxin has an average lifetime of 510 picoseconds. The consensus of least squares, maximum likelihood, Pade-Laplace, and distributional analyses of this decay is that more than 90% of the initial intensity comes from short lifetime components with lifetimes in the range 0.05 to 0.5 nanoseconds and the remaining shall fraction of initial intensity is essentially one component decaying with an average lifetime of about 2 nanoseconds. Both adiabatic mapping and combined thermodynamic perturbation and umbrella sampling simulations reveal the presence of two tryptophan-47 rotational isomers. One of the isomers corresponds closely to the crystallographic structure and the second is a new rotational isomer that is separated from the first by a rotation angle of about 220 degrees and an activation barrier of about 10 kcal/mole. We propose that the short lifetime components corresponds to conformers with tryptophan-47 approximately in the crystallographic orientation and the long lifetime component is the new rotational isomer identified in the simulations.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsJoseph F. Lakowicz
PublisherPubl by Int Soc for Optical Engineering
Pages92-99
Number of pages8
ISBN (Print)0819402451
StatePublished - Dec 1 1990
EventTime-Resolved Laser Spectroscopy in Biochemistry II - Los Angeles, CA, USA
Duration: Jan 15 1990Jan 17 1990

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1204 pt 1
ISSN (Print)0277-786X

Other

OtherTime-Resolved Laser Spectroscopy in Biochemistry II
CityLos Angeles, CA, USA
Period1/15/901/17/90

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Fluorescence of variant-3 scorpion neurotoxin: multiple decay components and multiple decay trytophan conformers'. Together they form a unique fingerprint.

  • Cite this

    Haydock, C., Sedarous, S. S., Bajzer, Z., & Prendergast, F. G. (1990). Fluorescence of variant-3 scorpion neurotoxin: multiple decay components and multiple decay trytophan conformers. In J. F. Lakowicz (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (pp. 92-99). (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 1204 pt 1). Publ by Int Soc for Optical Engineering.