Many antibiotics hit bacterial wall construction because their structure mimics which molecules?
AL-amino acids found in most proteins
BPolysaccharide chains of the capsule
CD-amino acids of the wall peptides
DPhytanyl side chains of the membrane
Answer & Solution
Correct answer: C. D-amino acids of the wall peptides
1. Peptidoglycan chains are cross-linked by peptides that carry both L- and D-amino acids.
2. D-glutamic acid and D-alanine are two of those unusual D-amino acids.
3. Ordinary proteins are built almost entirely from L-amino acids, so D-forms are a bacteria-specific target.
4. Many antibiotics therefore work by mimicking D-amino acids, acting on wall development.
5. Mimicking L-amino acids would interfere with the patient's own proteins, so that is the trap in the first option.
6. Capsule polysaccharides and archaeal phytanyl chains are not the target of this class of drugs.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 22 "Prokaryotes: Bacteria and Archaea", section 22.2 Structure of Prokaryotes_
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