Table 4

Most common secondary structures involving different types of π-turns and their immediate neighborsa

Secondary structures at positionsb


Turn

i-1

i

i+1

i+2

i+3

i+4

i+5

i+6

Number

Percentagec


π-HB

AAAa

E

E

T

T

T

T

E

E

245

70

PgAA

C

C

B

T

T

T

B

C

8

15

pAAa

E

E

T

T

T

T

E

E

10

42

π-NHB

AEAA

E

E

S

S

T

T

S

C

14

4

H

H

T

S

T

T

C

C

13

4

E

E

S

S

T

T

C

C

12

4

C

T

T

S

T

T

C

C

12

4

EAAa

E

E

C

T

T

S

C

E

86

31

E

E

C

T

T

C

C

E

68

24

C

B

C

T

T

S

C

B

16

6

EAAA

C

C

C

T

T

T

H

H

13

6

EAAE

E

E

C

S

S

C

E

E

73

41

AAaA

E

C

T

T

S

S

E

E

47

28

E

C

T

T

S

S

C

E

13

8

AEEa

H

H

T

S

T

T

C

C

10

6

C

T

T

S

T

T

C

C

10

6


aThe combination of secondary structures with >10 occurrence are shown. There is no occurrence of isolated AAAA and AAAa types of π-HB turns immediately after the α-helix.

bAccording to DSSP notation E: β-strand, T: hydrogen-bonded turn, B: isolated β-bridge, S: bend and we represent non-regular structure by C.

cBased on the number observed with the given combination of secondary structures (given in the previous column) relative the total number in the class.

Dasgupta and Chakrabarti BMC Structural Biology 2008 8:39   doi:10.1186/1472-6807-8-39

Open Data