Beta Strands And Beta Sheets

Question 1

What is the other common secondary structure besides the alpha helix?

Answer 1

Beta strands and Beta sheets

Stand and actives due in a are prati as of the polypeptide chlas hat arinaludes holy etended ach reside in of strand accounts for about osa in that are almost otal length in on tas ve the engrat coil of an a helix where each rest due ofte gont to 0.15 an is a ructure on. When pulips Strands are aranged side-bye- ide they form developed a theoretical inally proposed by Pauling and Corey at the some time they developed a theoretical model of the a helix.

Question 2

How are Beta strands stabilized in Beta sheets?

Answer 2

By hydrogen bonds between carbonyl oxygens and amide hydrogens on adjacent strands

Thus in proteins, the regions of structure are almost always found in sheets The hydrogen-bonded B strands can be on separate polypeptide chains or on different segments of the same chain. The B strands in a sheet can be either parallel (running in the same N- to C-termina direction) or antiparallel (running in opposite N- to C- terminal directions). When the B strands are antiparallel, the hydrogen bonds are nearly perpendicular to the extended polypeptide chains.

Question 3

Why are antiparallel Beta sheets more stable than parallel Beta sheets?

Answer 3

Possibly because the hydrogen bonds are distorted in the parallel arrangement

Parallel sheets are less stable than antiparallel sheets, possibly because the hydrogen bonds are distorted in the parallel arrangement. The ß sheet is sometimes called a pleated sheet since the planar peptide groups meet each other at angles, like the folds of an accordion.