Structure determines function. The 3D shape of a protein dictates how it interacts with other molecules, enabling biological processes like catalysis (enzymes), signaling, or immune responses. Misfolded structures can lead to diseases like Alzheimer's or cystic fibrosis.

• X-ray crystallography (high resolution but requires crystallization),
  
• NMR spectroscopy (good for small proteins in solution), and
  
• Cryo-electron microscopy (Cryo-EM) (useful for large complexes).
• AI models like AlphaFold can predict structures computationally.

• Primary: The linear sequence of amino acids.
  
• Secondary: Local folding patterns like alpha-helices and beta-sheets.
  
• Tertiary: The 3D structure of a single polypeptide chain.
  
• Quaternary: The arrangement of multiple polypeptide chains in a protein complex.

Proteins are made of amino acids, which are organic molecules composed of a central carbon atom bonded to an amino group (–NH₂), a carboxyl group (–COOH), a hydrogen atom, and a variable side chain (R group). A protein is formed when amino acids link together in a specific sequence via peptide bonds, forming a polypeptide chain.

The structures on FoldedThread are predicted protein structure from the AlphaFold Database is a 3D model of a protein generated using AI based on its amino acid sequence. While highly accurate, these models haven’t been proven by experimental methods like X-ray crystallography, cryo-electron microscopy, or NMR spectroscopy.