Protein Radius Of Gyration Calculator

Radius Of Gyration Formula:

\[ R_g = \sqrt{ \frac{\sum (m_i r_i^2)}{M} } \]

Radius Of Gyration (R_g):

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1. What Is The Radius Of Gyration?

The radius of gyration (R_g) is a measure of the distribution of mass around the center of mass in a protein or other molecular structure. It provides insight into the compactness and overall shape of the molecule.

2. How Does The Calculator Work?

The calculator uses the radius of gyration formula:

\[ R_g = \sqrt{ \frac{\sum (m_i r_i^2)}{M} } \]

Where:

\( m_i \) — Mass of individual components
\( r_i \) — Distance from center of mass
\( M \) — Total mass of the system

Explanation: The formula calculates the root mean square distance of mass elements from the center of mass, weighted by their masses.

3. Importance Of Radius Of Gyration

Details: The radius of gyration is crucial in structural biology for understanding protein folding, molecular shape, and conformational changes. It's particularly important in techniques like small-angle X-ray scattering (SAXS).

4. Using The Calculator

Tips: Enter masses and corresponding distances as comma-separated values. Both lists must have the same number of elements. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for mass and distance?
A: Use consistent units (e.g., atomic mass units for mass, angstroms for distance). The result will be in the same distance units as input.

Q2: How does radius of gyration relate to protein structure?
A: Smaller R_g values indicate more compact structures, while larger values suggest extended or unfolded conformations.

Q3: Can I use this for non-protein molecules?
A: Yes, the radius of gyration concept applies to any system with distributed mass, including polymers, nanoparticles, and other molecular structures.

Q4: What's the difference between R_g and hydrodynamic radius?
A: R_g describes mass distribution, while hydrodynamic radius (R_h) describes the effective size for diffusion in solution. They correlate but aren't identical.

Q5: How accurate is this calculation for real proteins?
A: This provides a theoretical estimate. For precise analysis, experimental techniques like SAXS or computational methods are typically used.