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Exploring Protein Structure and Function

Understand amino acids, protein hierarchy, isolation methods, and more to delve into the fascinating world of proteins. Learn about isoelectric points, denaturation, and protein crystallization. Discover the relationship between protein structure and function. Explore protein isolation techniques and assessment methods.

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Exploring Protein Structure and Function

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  1. Protein 制作人:许爱娱 20052503405 05级生物技术一班

  2. PROTEIN • Amino acid • Hierarchy of protein structure • Structure-function relationship • The property of protein • Protein isolation • Protein molecular weight

  3. Amino acid • Amino acid structure • Amino acid classification • UV-absorbing properties of Amino Acids • Isoelectric point • Reaction with Ninhydrin

  4. RETURN

  5. Neutral amino acid

  6. Neutral amino acid

  7. Acidic amino acid

  8. Basic amino acid

  9. Aromatic amino acid

  10. heterocyclic amino acid

  11. Isoelectric points • The isoelectric points of an amino acid occurs at the PH where the amino acid exists as the zwitterion

  12. Reaction with Ninhydrin

  13. Hierarchy of protein structure

  14. Primary structure • Primary :amino acid sequence • Due to covalent bond

  15. Peptide bond

  16. peptides

  17. Secondary structure • Regular,repeated coiling and folding of polypeptide backbone • Due to hydrogen bonding • Four patterns • alpha helix • beta sheet • beta turn • random coil

  18. the α-helix

  19. β-pleated sheed

  20. Theβ－ turn

  21. Some nice protein crystals

  22. tertiary • Complete three-dimensional structure • Due to weak interactions between side (R) groups as well as covalent disulfide bonds weak interactions hydrogen bonds electrostatic interactions (ionic bonds ) hydrophobic interactions van der waals interactions

  23. Tertiary structure formed through side chain interactions

  24. Structure-function relationship • Function is derived from structure • Structure is derived from sequence • Similar sequences have similar functions > similar function often implies evolutionary relatedness >>sequence similarity suggests common evolutionary origin >>>many diseases are related to anomaly of some proteins _sickle cell anemia and mad cow disease

  25. Sickle –cell disease

  26. The property of protein • Isoelectric points • Denaturation & renaturation • Solubility of proteins

  27. Isoelectric points

  28. Denaturation & renaturation Denaturation

  29. Solubility of proteins

  30. Protein isolation • Common methods used in protein isolation from cells or tissues: size exclusion (gel filtration) affinity chromatography ion exchange chromatography hydrophobic interaction chromatography • Assessment of protein purity and size by SDS PAGE (Sodium dodecylsulfate polyacrylamide gel electrophoresis)

  31. Gel-filtration chromatography

  32. Principle

  33. ion exchange chromatography

  34. Mesuration of molecular weight • Size exclusion • SDS_GEL

  35. SDS-PAGE Gel

  36. THE END THANK YOU

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