Table 3 

Statistics on the occurrence of different combinations of βturns within the common πturns. 

πturn 
Multiple βturns with their designations^{a} 


πHB 

AAAa (350) 
IIX (270), XIX (60), IXX (17) 
PgAA (52) 
IIXX (40), IIXI (8), XXI (1) 
AAAA (33) 
IXX (21), IIX (6), III (2), XII (1), XIX (1) 
πNHB 

AEAA (316) 
XXI (253), VIIIXI (45), VIIIXX (4), XVIa2I (1) 
EAAa (281) 
XIX (270) 
EAAA (219) 
XII (156), XIX (44), XXI (12) 
EAAE (176) 
XIX (130), XIVIII (16), VIa1XVIII (1), VIa1IX (1) 
AAaA (171) 
IXX (146) 
AEEa (167) 
XXII (131), VIIIXII (20), XVIbII (1) 


The number of occurrence is given in parentheses. ^{a }X indicates no characteristic βturn. The conventional nomenclature of βturns (viz., turn types I, II, VI, VIII, etc.) has been used. A multiple turn IIX indicates that there is a type I turn involving residues (i)(i+3), another type I involving (i+1)(i+4), and the turn type involving (i+2)(i+5) does not conform to any βturn type. 

Dasgupta and Chakrabarti BMC Structural Biology 2008 8:39 doi:10.1186/14726807839 