Ok. Gasymov et al., SOLUTION STRUCTURE BY SITE-DIRECTED TRYPTOPHAN FLUORESCENCE IN TEAR LIPOCALIN, Biochemical and biophysical research communications, 239(1), 1997, pp. 191-196
The solution structure of the G strand of human tear lipocalin was ded
uced by site directed tryptophan fluorescence (SDTF). The fluorescent
amino acid, tryptophan, was sequentially substituted for each native a
mino acid in the sequence of the G strand. The fluorescent properties
resolved alternating periodicity as predicted for beta sheet structure
, twists in the beta sheet, strand orientation in the lipocalin cavity
, and the relative depth of residues in the cavity. A distribution of
microstates with various orientations of dipoles in the side chain env
ironments of the G strand revealed mobility on the nanosecond time sca
le, SDTF is broadly applicable to most proteins and will complement x-
ray crystallography, site directed spin labeling by electron paramagne
tic resonance (EPR), and nuclear magnetic resonance (NMR) in the deter
mination of solution structure. (C) 1997 Academic Press.