BIOC192 Lecture 6 - Protein Structure and Protein Folding Flashcards
what are super secondary structures?
elements of secondary structure (i.e helices and strands) are connected by turns or regions of less ordered structure called loops of coils
what are common re occurring units of super secondary structures?
1) helix - turn - helix
2) Ξ² hairpin
3) greek key
4) strand - helix - strand
what is a Ξ² hairpin?
common anti-parallel loop with varying lengths
what is the greek key?
4 antiparallel strands (can be thought of as 1 long, bent hairpin)
what is a protein domain?
independently folded regions that often possess a specific binding function
what is the relationship between a protein domain and hydrophobic/hydrophilic parts?
a protein domain has a hydrophobic core and the hydrophilic parts of the protein are arranged on the surface in contact or near a solvent
what is the relationship between the number of protein domains in small and large proteins?
small proteins usually contain 1 protein domain where larger proteins may contain multiple domains
what are the 3 groups of protein families based on tertiary structure?
1) πͺ domain family
2) πͺ/Ξ² family
3) antiparallel Ξ² family
what is the relationship between protein domains used to make different types of proteins
domains are often βreusedβ by nature and combined with other domains to make proteins with different functions
what is the Afinsen experiment?
solution of ribonuclease A
β> added π-mercaptoethanol (reduces disulphide bonds) and urea (breaks everything that holds the protein together) β> denatured ribonuclease A
β> dialysis to remove π-metacarptoethanol and urea
β> air oxidation of the sulfur hydroxyl groups in the reduced ribonuclease
β> original solution of ribonuclease A
= meaning amino acids are the instructions for protein folding
what are the 4 steps of folding pathways to fold a protein?
1) formation of short secondary structure segments
2) nuclei come together, growing cooperatively to form a domain
3) domains come together (tertiary structure is still partly disordered)
4) small conformational adjustments to give compact native structure
what provides protein stability in aqueous solutions?
the hydrophobic core is the most important non-covalent contributor to protein stability
what are the 3 types of protein folding chaperones?
1) chaperone-independant
2) chaperone-dependant
3) chaperonin-dependant
what is an example of a chaperone-dependant protein folding chaperone?
Hsp70
what is an example of a chaperonin-dependant protein folding chaperone?
GroEL-GroES
