Nucleic Acids in Chemistry and Biology

DNA and RNA Structure 29

Table 2.3

Average helix parameters for the major DNA conformations

Helix Residues Twist per Displacement Rise per Base tilt

Groove Width/Å Groove Depth/Å

Structure type

sense per turn bp



°

bp D/Å

bp/Å

(t

°)

Sugar pucker

(minor) (major) (minor) (major)

A-DNA

R

11

32.7

4.5

2.5 620

C3

-

endo

11.0

2.7

2.8

13.5

DGGCCGGCC

R

11

32. 
    
    
    
    63. 6 3.03
    
    
    
    

12

C3

-

endo

9. 67.9

—

—

B-DNA

R

10

36

0.2 to

1.8 3.3

3.4

6C2

-

endo

5.7

11.7

7.5

8.8

dCGCGAATTCGCG R

9.7

37.1

—

3.34

1.2

C2

-

endo

3.8

11.7

—

—

C-DNA

R

9.33

38.5

1.0

3.31

8C3

-

exo

4.8

10.5

7.9

7.5

D-DNA

R

8

45

1.8

3.03

1 6C3

-

exo

1.3

8.9

6.7

5.8

T-DNA

R

8

45

1.43

3.4

6C2

-

endo

Narrow Wide

Deep

Shallow

Z-DNA

L

12

9,

51

2 to

3

3.7

7C3

-

endo (syn)

2.0

8.8

13.8

3.7

A-RNA

R

11

32.7

4.4

2.8

16–19

C3

-

endo

A

-RNA

R

12

30

4.4

3.0

10

C3

-

endo