Question

1,)The chemical composition of the peptidoglycan carrier bactoprenol is highly hydrophobic. Explain why this is necessary for bactroprenol to carry on its function

2.)Briefly describe the mechanism of action of beta-lactam antibiotics such as penicillin.

Answer 1

1. Because the complete Peptidoglycan synthesis occurs in three distinctive compartments of bacteria, namely the cytoplasm, the cytoplasmic membrane and the periplasmic space. Therefore for the transpeptidation the bactoprenol transport the peptidoglycan monomers across the cytoplasmic membrane and work with enzymes called transglycosylases to insert the monomers into the existing cell wall. As the new peptidoglycan monomers are inserted, transpeptidase enzymes (also known as penicillin-binding proteins) reform the peptide cross-links between the rows and layers of peptidoglycan making the cell wall strong

2. Penicillins prevents transpeptidation between layers by inhibiting transpeptidase enzyme. Penicillins and cephalosporins, as well as other beta-lactam antibiotics, mimic the D-alanyl-D-alanine (D-Ala-D-Ala) groups found at the terminus of the pentapeptide in most newly synthesized peptidoglycan monomers. Binding of the drug to the transpeptidase ties up the enzyme and prevents it from reforming the peptide cross-links between the rows and layers of peptidoglycan in the cell wall as new peptidoglycan monomers are added during bacterial cell growth. In addition, these antibiotics interfere with the bacterial controls that keep autolysins in check. Collectively, this results in degradation of the peptidoglycan and osmotic lysis of the bacterium.