M+C protein structure and function Flashcards
what are proteins made out of?
chains of amino acids joined by peptide bonds
what determines the properties of proteins and how they are folded?
side chains e.g. polar , no polar , electrically charged
what are the 2 secondary levels of structure?
alpha helix and beta pleated sheet
how are proteins held together?
by different ionic interactions
how are covalent bonds formed in the tertiary structure?
the oxidation of disulphide groups
what supports disulphide bond formation?
the oxidising redox environment of secretory pathways
what does glycolysation do to proteins?
makes them resistant to acids and adds gel like properties
how is keratin made?
formation of disulphide bridges between 2 cysteines
what is collagen and its use?
insoluble fibrous protein which helps tissues withstand stretching
give 3 features of fibroin
1) high glycine content
2) small non polar side chains
3) antiparallel beta pleated sheets
how is silk protein stored?
stored as an emulsion with c terminus in the middle ensuring solubility and making the core hydrophobic, side chains wrapped around the outside form bonds with water
describe the process of spinning a silk web
change in environment leads to unfolding, water and sodium leave lumen and lubricants enter lowering the PH and the thread leaves through spigot stripping of any excess water and molecules link forming strands
what is the protein in bread and describe how it works
gluten is the protein which forms a matrix trapping CO2 bubbles, as mechanical work stretches the dough more hydrogen bonds can form between chains of gluten subunits
how are gluten proteins linked?
by hydrogen bonds and disulphide bridges
what is the mutation in sickle cell anaemia?
polar hydrophilic glu replaced with non polar hydrophobic Val in haemoglobin
