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

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Post on 21-Dec-2015




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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.
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  • Ribbon Diagram Showing Secondary Structures in a Globular Protein
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  • 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)
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  • 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.
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  • Turns with cis-Proline: Type VI Type VIa Type VIb
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  • cis-trans Isomerization of Proline Residues Peptidyl-prolyl cis-trans isomerases accelerate the isomerization.
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  • 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.
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  • Domain and Motifs in Globular Proteins: Supersecondary Structure
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  • Some Common Motifs Found in Proteins motif hairpin motif barrels barrel
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