Vacuum-ultraviolet circular dichroism of Escherichia coli dihydrofolate reductase: Insight into the contribution of tryptophan residues

- We measured CD spectrum of wild-type and eight tryptophan mutant DHFRs down to 175 nm.
- CD spectrum of DHFR had a shoulder around 185 nm contrary to the theoretically calculated spectrum.
- Tryptophan side chains contribute to far-UV and VUV region of the CD spectrum of DHFR.