Time resolved fluorescence properties of phenylalanine in different environments. Comparison with molecular dynamics simulation.
Biophys Chem
; 73(1-2): 109-19, 1998 Jul 13.
Article
in En
| MEDLINE
| ID: mdl-9697301
ABSTRACT
Time resolved fluorescence of the phenylalanine residue (Phe) alone and included in the transmembrane domain (TMD) sequences of the epidermal growth factor receptor (EGFR) and ErbB-2 was studied using the synchrotron radiation source of light, and compared to molecular dynamics (MD) simulations. The fluorescence intensity decay is strongly sensitive to the environment. A mono-exponential decay was obtained for Phe amino acid alone in two different solvents and for Phe included in EGFR transmembrane sequence, with fluorescence lifetime values varying from 1.7 ns (EGFR) to 7.4 ns (Phe dissolved in water). In ErbB-2 transmembrane sequence three lifetimes were detected. The relative amplitude of the shortest one (0.14 ns) is smaller than 10%, whereas the others (0.6 and 2.2 ns) are almost equally represented. They have been attributed to different rotamers exchanging slowly. This interpretation is supported by MD simulations which evidence transitions in time series of the chi 1 dihedral angle of Phe observed in the case of ErbB-2. The anisotropy decays are similar for both peptides and indicate the presence of a correlation time in the nanosecond range (1-4 ns) and the probable existence of a very fast one (< 0.05 ns). Autocorrelation functions computed from MD simulations corroborate these results.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phenylalanine
/
Receptor, ErbB-2
/
ErbB Receptors
Type of study:
Prognostic_studies
Language:
En
Journal:
Biophys Chem
Year:
1998
Document type:
Article
Affiliation country:
France
Publication country:
HOLANDA
/
HOLLAND
/
NETHERLANDS
/
NL
/
PAISES BAJOS
/
THE NETHERLANDS