|MoBio||Beta Strand, Beta Sheet and Beta Barrel||Chapter 2|
In a β strand, the torsion angle of N-Cα-C-N in the backbone is about 120 degrees. The following figure shows the conformation of an ideal β strand. Note that the sidechains of two neighboring residues project in the opposite direction from the backbone.
Figure 2-C-6. An ideal β strand.
A β sheet consists of two or more hydrogen bonded β strands. The two neighboring β strands may be parallel if they are aligned in the same direction from one terminus (N or C) to the other, or anti-parallel if they are aligned in the opposite direction.
A β barrel is a closed β sheet.