Which element is required for conversion of G-actin into F-actin ?

Explanation

To answer the question about which element is required for the conversion of G-actin into F-actin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Actin Proteins**:
- Actin is a contractile protein found in skeletal muscle, existing in two forms: G-actin (globular actin) and F-actin (filamentous actin).

2. **Defining G-actin and F-actin**:
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