Peptide Binding to Calmodulin

How can such data be used to calculate the flaction o( the p tide which is free in solution (fp) and the fraction bound to calmodulin (fg)7 The additivity law for anisotropies (Eq. [10.6]) is propriate when the / are the fractional intensities, not the fractional populations. New 340 nm there is no change in intensity upon binding. Under 

Excitation at 295 nm. Revised and reprinted, with pennission, from Ret 40, Copyright O 1986, American Chemical Socieiy. 

Ftgure10.19. ntnlioaofdieMLCKpepddeltS20widicdiaDdalm (CAM). Revised and reprinted, widi pwmtsrion. from Ref. 40. Ccpyrigbr 01986, Amoican Chemical Socaely. 

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Peptide binding to calmodulin induces a large interdomain movement... 

Many more structure determinations of CaM-binding peptides have been carried out. For instance, the NMR structure determined by Ikura and co-workers for a CaM/CaMKK (from rat) complex (PDB ICKK) shows a calmodulin collapsed structure similar to those of CaM/smMLCK, CaM/ skMLCK, and CaM/CaMKIIa with the rCaMKK peptide cradled between calmodulin s C- and N-terminal domains. However, two features are different for CaM/rCaMKK. The first is that the peptide is bound in an inverted position compared to the others—that is, the N-terminal end of the rCaMKK peptide binds to CaM s N-terminal end and the C-terminal end binds to the C-terminal end rather than vice versa. This factor appears related to the clusters of basic residues on the target enzyme binding peptide—that is, when the... 

Malencik and Anderson have described a series of studies, using various probe strategies, on the interaction of peptides with calmodulin. Because calmodulin does not contain tryptophan, they were able to observe the increase in the anisotropy of tryptophan in various peptides on binding. For example, the anisotropy from the tryptophan of Polistes mastparan, a toxic peptide from the social wasp, on excitation at 294 nm, increased from around 0.02 to 0.13 on binding to calmodulin. In another study Malencik and Anderson characterized the association of melittin,... 

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