Diffusion constant of p53-GFP

Value 15.4 µm^2/sec Range: ±5.6 Table - link µm^2/sec
Organism Mammalian tissue culture cell
Reference Hinow P, Rogers CE, Barbieri CE, Pietenpol JA, Kenworthy AK, DiBenedetto E. The DNA binding activity of p53 displays reaction-diffusion kinetics. Biophys J. 2006 Jul 1 91(1):330-42 p.338 table 1PubMed ID16603489
Method Abstract: "In this study, [investigators] investigated the intracellular diffusion of a p53-GFP fusion protein using confocal fluorescence recovery after photobleaching [FRAP]. [They] show that the diffusion of p53-GFP within the nucleus is well described by a mathematical model for diffusion of particles that bind temporarily to a spatially homogeneous immobile structure with binding and release rates k1 and k2, respectively."
Comments Abstract: "The diffusion constant of p53-GFP was estimated to be Dp53-GFP=15.4 µm^2/s, significantly slower than that of GFP alone, DGFP=41.6 µm^2/s." P.336 left column 2nd paragraph: "The diffusion constant obtained for GFP in the nucleus (Table 1) is in close agreement with in vivo values published in the literature, e.g., D=43±11 μm^2/s (ref 24) and D=58±9 μm^2/s (ref 25) (although smaller values at ∼15μm^2/s have also been reported, (ref 7) and references therein)." P.336 right column top paragraph: "Significantly, the parameters of the three-parameter fit were identical within error for those obtained for the sequence-specific DNA-binding mutants and the wild-type p53 fusion protein (Table 1). This further substantiates the notion that specific DNA binding does not contribute significantly to the slowed diffusion of p53-GFP compared to GFP." P.337 right column bottom paragraph: "Nevertheless, [investigators] take [their] value k2=0.4/s as a sign of nonspecific DNA binding of unmodified p53. This conclusion is supported by [their] observation that the diffusional mobility of DNA binding mutants and wild-type p53-GFP are identical within error (Table 1)." See note above table
Entered by Uri M
ID 106693