Helical pitch, specifically regarding the DNA helix as described in the provided information, refers to each complete turn of the DNA spiral.
According to the reference dated 03-Jul-2022:
- Each turn of the DNA helix is called the pitch.
- It measures approximately 34 Angstroms (Å) or 3.4 nanometers (nm) in length along the axis of the helix.
- Each pitch contains roughly 10 base pairs (bp).
Understanding DNA Helical Pitch
The concept of helical pitch is fundamental to describing the structure of a helix, like the iconic double helix of DNA. It quantifies how much the helix advances linearly along its axis for one complete 360-degree turn.
For the B-form DNA helix, the pitch represents the vertical distance covered by one full rotation of the strands.
Key Characteristics of DNA Pitch
Here are the key parameters of the DNA pitch as given:
- Definition: One complete turn of the helix.
- Length: ~34 Å or ~3.4 nm.
- Content: Approximately 10 base pairs.
These measurements are crucial for understanding the geometry and stability of the DNA molecule. Knowing the pitch allows scientists to calculate other structural properties, such as the rise per base pair (pitch length divided by the number of base pairs per pitch).
Understanding helical pitch is important in various fields, including:
- Molecular Biology: Studying DNA structure and interactions.
- Biophysics: Analyzing the physical properties of biomolecules.
- Nanotechnology: Designing structures that interact with DNA.
In summary, based on the provided reference, the helical pitch of DNA is the length of one full spiral turn, measuring about 3.4 nm and containing approximately 10 base pairs.
