DNA Penetration into a Lysozyme Layer at the Surface of Aqueous Solutions

Abstract

The interactions of DNA with lysozyme in the surface layer were studied by performing infrared reflection–absorption spectroscopy (IRRAS), ellipsometry, surface tensiometry, surface dilational rheology, and atomic force microscopy (AFM). A concentrated DNA solution was injected into an aqueous subphase underneath a spread lysozyme layer. While the optical properties of the surface layer changed fast after DNA injection, the dynamic dilational surface elasticity almost did not change, thereby indicating no continuous network formation of DNA/lysozyme complexes, unlike the case of DNA interactions with a monolayer of a cationic synthetic polyelectrolyte. A relatively fast increase in optical signals after a DNA injection under a lysozyme layer indicates that DNA penetration is controlled by diffusion. At low surface pressures, the AFM images show the formation of long strands in the surface layer. Increased surface compression does not lead to the formation of a network of DNA/lysozyme aggregates as in the case of a mixed layer of DNA and synthetic polyelectrolytes, but to the appearance of some folds and ridges in the layer. The formation of more disordered aggregates is presumably a consequence of weaker interactions of lysozyme with duplex DNA and the stabilization, at the same time, of loops of unpaired nucleotides at high local lysozyme concentrations in the surface layer.

How Does Airway Surface Liquid Composition Vary in Different Pulmonary Diseases, and How Can We Use This Knowledge to Model Microbial Infections?

“…GlcNAc, which has previously been added to certain airway-mimicking media [26,81], may also lead to a decrease in lysozyme activity, because it is a competitive inhibitor of the enzyme [205,206]. Lysozyme is also known to bind to DNA, forming highly charged lysozyme-DNA complexes that alter nucleic function and make lysozyme a potent antiviral [207,208]. This antiviral activity is distinct from the catalytic mechanism responsible for the antibacterial activity of lysozyme [208].…”

DNA strand displacement based computational systems and their applications

“…The length of one double helix of B-type DNA is 3.4 nm, and the width is 2 nm. A single strand of DNA is flexible, whereas the double strand of DNA is among the stiffest polymers, with a persistence length of 50 nm in 0.1 M aqueous NaCl (Chirkov et al, 2022). Therefore, DNA strands and their complexes can be utilized as computational devices (Chen et al, 2020; Chen et al, 2022a;Xu et al, 2022).So far, many DNA computing models have been proposed.…”