Study of Cytochrome c-DNA Interaction – Evaluation of Binding Sites on the Redox Protein

Abstract

Artificial assemblies consisting of the cationic cytochrome c (cyt c) and double-stranded DNA are interesting for the field of biohybrid systems because of the high electro-activity of the incorporated redox protein. However, little is known about the interactions between these two biomolecules. Here, the complex of reduced cyt c and a 41 base pair oligonucleotide was characterized in solution as a function of pH and ionic strength. Persistent cyt c-DNA agglomerates were observed by UV-vis and DLS (dynamic light scattering) at pH 5.0 and low ionic strength. The strength of the interaction was attenuated by raising the pH or the ionic strength. At pH 7.0 agglomerates were not formed, allowing interaction analysis by NMR spectroscopy. Using TROSY (transverse relaxation-optimized spectroscopy)-HSQC (heteronuclear single quantum coherence) experiments it was possible to identify the DNA binding site on the cyt c surface. Numerous residues surrounding the exposed heme edge of cyt c were involved in transient binding to DNA under these conditions. This result was supported by SEC (size exclusion chromatography) experiments at pH 7.0 showing that the interaction is sufficient for co-elution of cyt c and DNA.

Interaction of Flavin-Dependent Fructose Dehydrogenase with Cytochrome c as Basis for the Construction of Biomacromolecular Architectures on Electrodes

“…It has to be emphasized here that DNA acts only as a structural support to bind a large amount of cyt c. 40 This is based on a rather strong interaction in acidic solutions which is mainly of electrostatic nature and has been elucidated previously. 41 The DNA molecule has no redox activity in the potential range tested here.…”

Adsorption characteristics of Cytochrome c/DNA complex Langmuir molecular assemblies at the air–water interface: a surface area-normalized isotherm study

“…However, the extent of interaction may depend upon different microenvironment. 32 For the complex monolayer at the interface, DNA has been used as the building block for the Cyt c/l-DNA complex molecular network. In our work, pH of the subphase aer spreading Cyt c/l-DNA mixed solution was 6.2.…”

“…30,31 Research suggests that Cyt c/DNA multilayered systems exhibit highest accumulations of redox active materials. 32 However, for specic device or applications, it is very crucial to tailor the properties by changing the orientation of DNA/protein complex assemblies onto solid substrate. LB technique, in this regard, is an elegant choice because of its ability to manipulate molecular orientation and prepare ultrathin lms with highest materials transfer ratio.…”

A precursor-approach in constructing 3D ITO electrodes for the improved performance of photosystem I-cyt c photobioelectrodes

“…In several studies on combination between DNA-cyt c it has been demonstrated that electron exchange between cyt c-cyt c can be realized. 295,296 An intensive study by Stieger et Here, combination with the third biomolecule, DNA, has been employed and stable photoactive multilayers (PSI-cyt c-DNA) n have been achieved. 85 c) integration of PSI-cyt c inside a 3D electrode architecture.…”