Table 1. Distances between residues used in dye-labeling and tryptophans of native apoflavodoxin.

From	To
	Trp74	Trp128	Trp167
Cys1	21.3 Å	24.3 Å	18.3 Å
Cys69	12.8 Å	26.4 Å	24.5 Å
Cys131	25.3 Å	8.7 Å	15.2 Å
Cys178	26.1 Å	19.3 Å	14.8 Å

The distances reported are between C^7a of the tryptophan indicated and C^α of the residue to be dye-labeled, as measured by using PyMol (Schrödinger, LLC, Palo Alto, Ca, USA) and the crystal structure of A. vinelandii flavodoxin (pdb ID 1YOB [56]).