title: Dynamics of a membrane-bound tryptophan analog in environments of varying hydration: a fluorescence approach.
abstract: Tryptophan octyl ester (TOE) represents an important model for membrane-bound tryptophan residues. In this article, we have employed a combination of wavelength-selective fluorescence and time-resolved fluorescence spectroscopies to monitor the effect of varying degrees of hydration on the dynamics of TOE in reverse micellar environments formed by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in isooctane. Our results show that TOE exhibits red edge excitation shift (REES) and other wavelength-selective fluorescence effects when bound to reverse micelles of AOT. Fluorescence parameters such as intensity, emission maximum, anisotropy, and lifetime of TOE in reverse micelles of AOT depend on [water]/[surfactant] molar ratio (w (o)). These results are relevant and potentially useful for analyzing dynamics of proteins or peptides bound to membranes or membrane-mimetic media under conditions of changing hydration.
authors.affiliation: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India. amit@ccmb.res.in
authors.forename: Amitabha
authors.initials: A
authors.lastname: Chattopadhyay
authors.forename: Ajuna
authors.initials: A
authors.lastname: Arora
authors.forename: Devaki A
authors.initials: DA
authors.lastname: Kelkar
mesh_terms: D032701:Biomimetics; D004143:Dioctyl Sulfosuccinic Acid / Q000737:chemistry; D005453:Fluorescence; D008566:Membranes / Q000737:chemistry*; D008823:Micelles; D009795:Octanes / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013501:Surface-Active Agents / Q000737:chemistry; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D008823:Micelles; D009795:Octanes; D013501:Surface-Active Agents; C097263:tryptophan octyl ester; D014867:Water; D004143:Dioctyl Sulfosuccinic Acid; D014364:Tryptophan; C045798:2,2,4-trimethylpentane