What are the differences between B-DNA and Z-DNA?

Question

Accepted Answer

B-DNA and Z-DNA are two of three common DNA conformations. There are several significant differences between the two.

Basis of differentiation

B-DNA

Z-DNA

Distinguishing characteristic

Has a right-handed double helix structure with the two strands running in different directions

Has a left-handed double helix structure with a distinct zigzag appearance of backbone

Occurrence

Commonly occurring DNA form under normal physiological conditions

Less common DNA form under normal physiological conditions

Condition for formation

Normal physiological conditions

High salt concentration

Helical width

2 nm

1.8 nm

Number of base pairs in each turn

Each turn comprises 10.5 base pairs with a length of 3.4 nm

Each turns comprises 12 base pairs with a length of 4.56 nm

Distance between adjacent deoxyribonucleotides

0.34 nm

0.37 nm

Structure of major groove

Wide and deep

Narrow and deep

Structure of minor groove

Narrow and deep

Wide and shallow

Stability

Stable and easy to observe

Unstable and difficult to observe

Basis of differentiation	B-DNA	Z-DNA
Distinguishing characteristic	Has a right-handed double helix structure with the two strands running in different directions	Has a left-handed double helix structure with a distinct zigzag appearance of backbone
Occurrence	Commonly occurring DNA form under normal physiological conditions	Less common DNA form under normal physiological conditions
Condition for formation	Normal physiological conditions	High salt concentration
Helical width	2 nm	1.8 nm
Number of base pairs in each turn	Each turn comprises 10.5 base pairs with a length of 3.4 nm	Each turns comprises 12 base pairs with a length of 4.56 nm
Distance between adjacent deoxyribonucleotides	0.34 nm	0.37 nm
Structure of major groove	Wide and deep	Narrow and deep
Structure of minor groove	Narrow and deep	Wide and shallow
Stability	Stable and easy to observe	Unstable and difficult to observe