Distance-decay constant

Cai et al. [7e] investigated electron and hole transfer in various polynucleotide duplexes and compared them with previous results found for salmon sperm DNA, to examine the effect of base sequence on excess electron and hole transfer along the DNA 71-way at low temperature. Electron and hole transfer in DNA was found to be clearly base sequence dependent. In glassy aqueous systems (7M LiBr glasses at 77 K), excess electron-transfer rates increase in the order polydIdC-polydIdC<salmon testes DNAexcess electron and hole transfer rates increase in the order polyC-polyG<salmon testes DNATransfer distances at 1 min and distance decay constants for electron and hole transfer from base radicals to MX in polynucleotides-MX and DNA-MX at 77 K are derived and compiled in Table 3. This table clearly shows that the electron-transfer rate from donor sites decreases in... 

Table 3 Transfer distances and distance decay constants for electron and hole transfer to...

DNA < polyA-polyU. The electron-transfer rate from donor sites decreases in the order U T > C(N3)D and the hole transfer rate from donor sites decreases in the order A + > G +. The distance decay constant, b, for electron... 

The Ru-protein data points are scattered around the Ru azurin fi = 1.1 A exponential distance decay. More than three-fourths of the Ru protein ET rates fall in a 1.0 to 1.3 A y3-value zone. The data in Figure 5 suggest that a canonical distance decay constant will not describe long-range electron tunneling in proteins. Rates at a single distance can differ by as much as a factor of 10 and D/A distances that differ by as much as 5 A can produce identical rates. The... 

Table 1. Transfer distance and distance decay constant for hole/electron transfer. ...

The distance decay constant / (see below) in Miller et al. s original study was 0.9 per CH2, using ferricyanide and iron(IH) hexahydrate [44]. In a later study which accounted more thoroughly for double layer effects, 2 was determined to be 1 eV for kinetically facile redox probes such as ferricyanide, 1.3 eV for Ru-hexamine and 2.1 eV for iron(III) hexahydrate. With a better understanding of the redox probe behavior, f was found to be 1.08 + 0.20 per CH2 and independent of the redox couple and electrode potential [96]. Pre-exponential factors were also extracted from the Tafel plots. The edge-to-edge rate constants (extrapolated) are approximately 10 -10 s for all redox probes, which is reasonable for outer-sphere electron transfer. The pre-exponential factors are 5 x lO s [96]. 

Table 1. Summary of electron-transfer distance decay constants for n-alkanethiol SAMs and related bilayer systems.

P-sheets, a-hcliccs). The coupling efficiency can be determined from the variation of O as a function of R. A linear O /R relationship implies that will be an exponential function of R the distance-decay constant is determined by the slope of the oi/R plot and the value of... 

Investigations of Ru(tpy)2 (tpy = 2.2 6.2"-tcrpyridinc) luminescence quenching by Fe(OH2)6 in aqueous acidic glasses have produced a distance decay constant of 1.59 0.05 4., 20,85 substantially larger than those... 

A distance decay constant of -0.5 A has been extracted from work on... 

In order to obtain a deeper insight into ET mechanism in azurin, current-distance measurements under electrochemical control provided the distance decay constants of the ET process [31]. 

Artes JM, Diez-Perez I, Sanz F, Gorostiza P (2011) Direct measurement of electron transfer distance decay constants of single redox proteins by electrochemical tunneling spectroscopy. ACS Nano 5 2060-2066... 

---