23. HIV, the virus that causes AIDS, avoids an immune response by frequent error
ID: 3514309 • Letter: 2
Question
23. HIV, the virus that causes AIDS, avoids an immune response by frequent errors in replication resulting in the replacement of one or many amino acid residues. Such substitutions may or may not influence antibody binding of i antigen. Which of the following best represents an example of an antigen whose antibody bonding affinity is greatly decreased? A. An antigen with an E for D substitution. B. An antigen with an N for Q substitution. C. An antigen with a D for H substitution. D. An antigen with an I for L substitution. E. An antigen with a T for S substitution.Explanation / Answer
The substitution in aminoacid has to influence the binding to of antibody indicates the susbstitute has to introduce a drastic change in shape or charge.
The answer is c wherein an acidic aminoacid is substituted to a basic aminoacid (aspartic acid to histidine).
This will bring a change in the structure as the aminoacid tends to orient itself differently in the protein than the wild type thus contributing to the antigenic shift.
If you consider the other options all the substitutions are with quite similar aminoacids like aspartic acid to glutamic acid wherein both are acidic and will contribute to slight change which will not affect the structure of the protein
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.