14-3-3 Proteins bind phosphorylated sequences in proteins and regulate multiple cellular functions. For the first time, we show that pure recombinant human 14-3-3 ζ, γ, ε and τ isofoms hydrolyze ATP with similar Km and kcat values. In sharp contrast the sigma isoform has no detectable activity. Docking studies identify two putative binding pockets in 14-3-3 zeta. Mutation of D124A in the amphipathic pocket enhances binding affinity and catalysis. Mutation of a critical Arg (R55A) at the dimer interface in zeta reduces binding and decreases catalysis. These experimental results coincide with a binding pose at the dimer interface. This newly identified function could be a moon lighting function in some of these isoforms.
Keywords: 14-3-3; 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; AMP-PCP; ATP hydrolysis; ATP-γ-S; Chaperone; Ci; Docking; HEPES; MALDI; Mutation; Ni-NTA; PDB; PLP; RMSD; TOF; WT; adenosine 5′-(3-thiotriphosphate); adenylylmethylenediphosphonate; curie; matrix assisted laser desorption ionization; nickel-nitriloacetic acid; piecewise linear pairwise potential; protein data bank; root mean-square deviation; tandem time of flight; wild-type.
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