An $\alpha$-helix has the sequence: NH₃⁺-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-. The carbonyl oxygen (in the peptide bond) of the histidine residue is hydrogen bonded to the amide nitrogen of A) Asp. B) Lys. C) Trp. D) Ala.

Question

Quizplus · Accepted Answer

The carbonyl oxygen of the histidine residue is hydrogen bonded to the amide nitrogen of lysine, which is two residues away in the sequence (₃^+****-Ser-Glu-Gly-Asp-**Trp-Gln**-Leu-**His-Val**-Phe-Ala-Lys-**Val-Glu**-COO-). None of the other options are two residues away from histidine and have an amide nitrogen to form a hydrogen bond.

An α\alphaα -Helix Has the Sequence: NH3+-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-

An $\alpha$ -Helix Has the Sequence: NH₃⁺-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-