Question
I have to answer this question and I have read my textbook so many times and still the only part I get from it is this: "The mechanisms of antibody action consists of inhibition of the cell wall synthesis, inhibition of protein synthesis, inhibit DNA replication, and inhibit the synthesis or activity of an important enzyme required for bacterial cell metabolism." and I am not even sure that is all of it but it does not go into details about it so I am unable to describe them. I have even tried searching the internet but come up empty handed. This is a biotechnology class. Please help.
Explanation / Answer
The mechanism of antibody: 1. Inhibition of cell wall synthesis: - Bacterial cell wall is made up of peptidoglycan. Peptidoglycan is unique among biological polymers because it contains L and D isomers of its constituent amino acids. Antibodies produce enzymes that are responsible for the natural turnover of cell wall polymers to permit growth of the cells by producing weak points within the peptidoglycan structure, allowing it for expansion of the cell wall structure. This activity causes breakdown of peptidoglycan and leading to osmotic fragility of cell and ultimately to cell lysis. 2.Inhibition of protein synthesis: - They inhibit the process of protein synthesis. They prevent the initiation of protein synthesis by binding to the bacterial ribosomes and blocking the binding of initiator N-formylmethionine tRNA to the ribosome. It also prevents the dissociation of ribosomes into their subunits, leaving them in their primitive form, i.e. 70S or 80S. 3. Inhibit DNA replication: - They bind to the enzyme DNA topoisomerase which is essential for DNA replication and allows supercoils to be relaxed and reformed. Inhibition of DNA topoisomerase blocks the ligation step of cell cycle that generates single or double stranded breaks, harming the integrity of the genome. This activity lead to apoptosis and cell death. 4. Inhibiting the synthesis or activity of enzymes that are important for bacterial cell metabolism: - They inhibit the bacterial enzymes that are required for the synthesis of tetrahydrofolic acid (THF), the vitamin form of folic acid essential for 1-carbon tranfer reactions. So, the essential metabolites or growth factors that are needed in bacterial metabolism are not synthesized, leading to cell death.