TABLE 1.

Experimental and theoretical interdye distances

Experimentally derived distances for Alexa 488 coupled to V649C and Alexa 647 coupled to A454C are presented for direct comparison with the distances obtained from analysis performed as described previously (41), based on the structure of the dyes, the linker length, and the structure of Klentaq1 (see “Experimental Procedures”). R_Cβ is the distance between the Cβ atoms of the amino acid used for linking the dye to Klentaq1. 〈R_DA〉_E is the FRET averaged mean distance given as: 〈R_DA〉_E = R₀ (〈E〉⁻¹ − 1)^1/6. The following structures from the Protein Data Bank were used (closed, 1QTM; open, 1KTQ).

FRET states	Closed	Nucleotide binding	Open
Experimental distances
〈RDA〉E	49.5 ± 0.8 Å	55.5 ± 0.8 Å	60.7 ± 0.6 Å
Calculated distances
〈RDA〉E	49.9 Å	NA	62.4 Å
RCβ	40.2 Å	NA	52.0 Å