August 30, 2007
Molecules of life – Lysozyme
The most interesting properties of the living organisms are self-defence. Generally, all living organisms are exposed to two types of threats – predators and parasites. In this article we will discuss the very basic technique fro organism protection from the simplest parasites – bacterial infection.
The biggest problem for an organism protection system is to get access to the internal part of bacterial cell. Usually bacterial wall is covered by polysaccharide wall, formed by N-acetylglucosamine and N-acetylmuramic acid sugars.
In highest organisms this cell-wall is demolished by breaking of the beta (1-4) glycosidic bond between these sugars by Lysozyme. Lysozyme usually present in the all mucosal secretion such as saliva and tears. The highest concentration of this enzyme, about 3% from all proteins is observed in chicken egg-white.
Lysozyme structure is very simple – this is a single domain protein which work as a monomer. The Lysozyme structure was discovered in 1965 by David Phillips. First description of this protein was done in 1922 by Alexander Fleming. From this time Lysozyme is one of the most used proteins in educational purposes. It is very cheap and easy to purify this protein from the chicken egg in almost all amounts. Furthermore the Lysozyme crystallization is an easiest experiment between all other protein crystallization experiments. Even novice technician can repeat Lysozyme crystallization without any problems.
In most of the organism this protein used for protection, but as everywhere, somebody can yuse goods for evil purposes. So in some bacteriophage viruses the Lysozyme from their tail is used to break the bacterial wall for further infection.