Biarsenical-tetracysteine complex

Fig. 8.1-1 A comparison of the relative sizes of CFP and the biarsenical-tetracysteine complex. The atoms comprising the chromophores are shown in color with the peptide backbone depicted in green.

The high stability of the biarsenical-tetracysteine complex and the sensitivity of its fluorescence polarization to localized protein dynamics complex has recently been used to probe the structure of the pentameric oligomer of phospholamban [17], a key regulator of contractility in the heart. Tetracysteine sites were formed at three internal sites within the n-helical region involved in oligomerization by mutation of existing amino acids at positions 5, 6,... 

One noticeable feature of the biarsenical-tetracysteine system is the high stability of the complex when formed, with off-rates up to weeks in vitro [8]. 

Figure 4.25 Biarsenical ligands. Synthesis of Flash EDT2 and proposed structure of its complex with an a-helical tetracysteine-containing peptide or protein domain. The structure is drawn with the i and i +4 thiols bridged by one arsenic and the / + 1 and / + 5 thiols bridged by the other (Reproduced from Griffin et al., 1998, Fig. 1).

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