Which of the following peptides can coexist in both cis- and trans-conformation?
Val-Pro-CONH2 is the scientifically accurate answer to this question. Within the study of Peptide and Ramachandran plo, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of Val-Pro-CONH2 directly address what is being asked. Among the other options, Ala-Ala-CONH2, Pro-Gly-CONH2, and Asn-Gly-CONH2 do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.
Ref: Campbell Biology, Urry et al., 12th Ed.