Conformation cation binding

It has been established by substitution of for Mg that, prior to phosphorylation, the divalent cation binds at a cytosolic site with a stoichiometry of about 1 mol per phosphorylation site [124,125]. These experiments also demonstrated that the phosphorylation rate is sensitive to the nature of the divalent cation bound. With Mg bound, the phosphorylation rate is about 20 times faster than with Ca bound. The divalent cation dissociates after dephosphorylation, suggesting that it is tightly bound to the phosphoenzyme during the reaction cycle. It was also demonstrated that the type of divalent cation that occupies the divalent cation site required for phosphorylation is important for the step 2K E2-P to 2K E2 P to 2K E2 [124,125]. With Mg bound, the 2K E2-P conformer is -sensitive, whereas with Ca bound, the intermediate is -insensitive. 

Modulation of the Bioactive Conformation of Transforming Growth Factor Possible Implications of Cation Binding for Biological Function... 

Bocharov EV, Pavlov KV, Blommers MJJ, Arvinte T, Arseniev AS (2008) Modulation of the Bioactive Conformation of Transforming Growth Factor P Possible Implications of Cation Binding for Biological Fimction. 273 155-181 Boiteau L, see Pascal R (2005) 259 69-122 Bolhuis PG, see Dellago C (2007) 268 291-317... 

Figure 14, Schematic drawings of conformational changes upon cation binding by glymes, crown ethers, and cryptands (D denotes donor atom) also shown are the slopes (a) and intercepts TASo oi AH-TAS plots as measures of conformational change and desolvation.

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