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. Author manuscript; available in PMC: 2017 Feb 1.
Published in final edited form as: Chem Biol Drug Des. 2015 Sep 16;87(2):171–181. doi: 10.1111/cbdd.12651

Figure 1.

Figure 1

Labeling scheme for the detection of hydrophobic cleft opening via self-quenching. (Left) The N-domain of cTnC is shown in the closed conformation with residues 13 (lower site) and 51 (upper site) shown in red. Both residues 13 and 51 are shown bound to TAMRA-5-maleimide. (Right) Upon binding to Ca2+, the N-domain of cTnC is able to adopt an open conformation which allows for interaction with cTnI. Ca2+ is shown in orange coordinated in cTnC site II. The residues 13 and 51 can be seen to move further apart in the open conformation, taking the attached TAMRA molecules with them. As the two TAMRA molecules separate, the ability for TAMRA to self-quench is greatly reduced resulting in higher observed fluorescence intensity (structures adapted from PDBID structures 1SPY, left, and 1J1E, right) (42,53).