Tryptophan analogs were biosynthetically incorporated into the tryptophan sites of DsbA protein to investigate the spectroscopic characteristics, local environments of tryptophans. This technique by using tryptophan-analog labeling may be of potential application to studying structure-function relationships and protein-protein interactions. 5-hydroxytryptophan labeled DsbA protein presents a fluorescence excitation wavelength at 315 nm and an emission near 340 nm. The chemical shifts of Trp76 and Trp126 in 5-fluorotryptophan labeled DsbA were identified in ¹⁹F-NMR spectra, and change of the chemical shift of Trp76 can reflect the conformational change of DsbA protein during redox reaction. The future work is to use specific fluorescence and ¹⁹F-NMR of labeled DsbA protein to study its redox properties and interaction with substrates.