 Figure 
14. Gamma turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+2. The dihedral angles of residue i+1 are (70, -60) and (-70, 60) for 
phi and psi of the classical and inverse gamma turns.  (from http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
Figure 
14. Gamma turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+2. The dihedral angles of residue i+1 are (70, -60) and (-70, 60) for 
phi and psi of the classical and inverse gamma turns.  (from http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
 Figure 
15. Type I turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+3. The backbone dihedral angles of residue are (-60, -30) and (-90, 0) 
of residues i+1 and i+2, respectively of the type I turn. Proline is often 
found in position i+1 in type I turns as its phi angle is restricted to -60 and 
its imide nitrogen does not require a hydrogen bond. Glycine is favored in this 
position in the type II' as it requires a positive (left-handed) phi value.
(from
http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
Figure 
15. Type I turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+3. The backbone dihedral angles of residue are (-60, -30) and (-90, 0) 
of residues i+1 and i+2, respectively of the type I turn. Proline is often 
found in position i+1 in type I turns as its phi angle is restricted to -60 and 
its imide nitrogen does not require a hydrogen bond. Glycine is favored in this 
position in the type II' as it requires a positive (left-handed) phi value.
(from
http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
 Figure 
16. Type II turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+3. The backbone dihedral angles of residue are (-60, 120) and (80, 0) 
of residues i+1 and i+2, respectively of the type II turn. Proline is often 
found in position i+1 in type I turns as its phi angle is restricted to -60 and 
its imide nitrogen does not require a hydrogen bond. Glycine is favored in this 
position in the type II' as it requires a positive (left-handed) phi value.
(from http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
Figure 
16. Type II turn. Note the hydrogen bond between CO of residue i and NH of 
residue i+3. The backbone dihedral angles of residue are (-60, 120) and (80, 0) 
of residues i+1 and i+2, respectively of the type II turn. Proline is often 
found in position i+1 in type I turns as its phi angle is restricted to -60 and 
its imide nitrogen does not require a hydrogen bond. Glycine is favored in this 
position in the type II' as it requires a positive (left-handed) phi value.
(from http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)
 
 
  3.10 
Helix
Figure 17. Type III turn. Note the hydrogen bond between CO of residue i and 
NH of residue i+3. This is a single turn of right-handed (III) and left-handed 
(III') 3.10 helix, respectively. The backbone dihedral angles of residue are 
(-60, -30) and (-60, -30) of residues i+1 and i+2, respectively of the classical 
type III turn. (from http://www.cryst.bbk.ac.uk/PPS2/course/section8/ss-960531_16.html#HEADING15)