Question

Explain why α-helices are most commonly observed in transmembrane protein sequences when the distance from one side of a membrane to the other can be spanned by significantly fewer amino acids in a β-strand conformation.

Match the items in the left column to the appropriate blanks in the sentences on the right.

prevents within a The structure of an a-helix promotes stretch of amino acids, and at the same time contiguous interactions with other important molecules involved in in the form of cell membrane allows In contrast, a B-strand would allow in a manner which may not be on a noncontiguous stretch of amino acids. Further, intramolecular which is necessary for maintaining the stability of the would not occur in the structure of a B-strand protein sequence van der Waals forces ionic bonding H-bonding H-bond donors or H-bond аcсeptors electron donors or acceptors

Answer 1

Ans- Alpha helices are most commonly observed in transmembrane protein sequences because the helical structure can satisfy all hydrogen bonds in the backbone internally, which in turn does not leave any polar groups exposed to the membrane if the side chains are hydrophobic.

Ans-Match the items-:

The structure of an alpha helix promotes H- bonding within a non-contiguous stretch of amino acids, and at the same time allows interactions with other molecules involved in ionic bonding in the form of protein sequence.