globular proteins proteins with a compact folded structure (with an interior and exterior),...

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  • Slide 1
  • Globular Proteins Proteins with a compact folded structure (with an interior and exterior), generally containing different types of secondary structure elements as well as irregular regions. Note: the vast majority of proteins are globular.
  • Slide 2
  • Ribbon Diagram Showing Secondary Structures in a Globular Protein
  • Slide 3
  • Some Globular Protein Structures Myoglobin Hemoglobin (complex of 4 polypeptide chains or subunits) Triose phosphate isomerase (complex of 2 subunits)20S Proteasome (complex of 28 subunits)
  • Slide 4
  • Slide 5
  • Slide 6
  • Additional Elements of Structure: Turns turns turn R2 often Pro Most common type of turn R3 never Pro trans-Pro (above) or cis-Pro (in Type VI turns) often found in turns, but rarely in helices and sheets.
  • Slide 7
  • Slide 8
  • Turns with cis-Proline: Type VI Type VIa Type VIb
  • Slide 9
  • cis-trans Isomerization of Proline Residues Peptidyl-prolyl cis-trans isomerases accelerate the isomerization.
  • Slide 10
  • Additional Elements of Structure: Loops Irregularly structured elements More disordered and flexible than turns Connects secondary structure elements Variable in length and shape Frequently form binding sites and enzyme active sites The N- and C-terminal arms of proteins are also generally more disordered and irregularly structured.
  • Slide 11
  • Domain and Motifs in Globular Proteins: Supersecondary Structure
  • Slide 12
  • Some Common Motifs Found in Proteins motif hairpin motif barrels barrel
  • Slide 13