CHMA 2002 - Module 2D: Protein folding

The folded structure of a protein is 3d and called it's

native conformation

two kinds of folding at the secondary level are called

alpha helix and beta sheet

The primary structure has influence on later folding because of the the

non-covalent interactions in the primary structure

-H bonding

- hydrophobic interaction

-ionic interactions )salt bridge, ion pairing)

-Disulphide bonding (this is covalent)

hydrophobic interactions are

lipophilic

Alpha helix coils are formed by

intramolecular hydrogen bonds formed by the Hydrogen from the amino to the oxygen from the carboxyl

examples of alpha helix proteins

collagen and alpha keratin

collagen is a super helical protein, meaning it has a

triple helix

the three helixes of collagen are joined by

inter molecular hydrogen bonds

alpha keratin is a

coiled coil

how is alpha keratin fromed

two alpha helices make a dimer, which combine to make protofilaments, two of which combine to make protofibrils, four of which combine to make microfibrils which constitute a hair.

super secondary structures are also called

structural motifs

structural motifs are in what level of protein folding

secondary

a tertiary structure is a combination of several

structural motifs to from a compact unit for a specific biological function (a domain)

the shape of GFP is a

beta barrel

quaternary structures contain more than one

subunit (multiple tertiary structures)

Homotypic proteins are

quaternary proteins containing identical subunits

Heterotypic proteins are

quaternary proteins containing different subunits

The hydropathy index measures the

hydrophobicity of a protein (higher numbers are more hydrophobic, lower numbers are least hydrophobic and more polar)

The hydropathy can also be used to find

membrane-bound domains of proteins

the highest energy level of proteins during folding is

primary, decreasing in energy successively through to the tertiary and quaternary structure

Some folding processes require assistance from

molecular chaperones

molecular chaperones help with

-folding

-protects proteins from unfolding or misfolding

-protects from heat (HSP)

Protein unfolding is the loss of

biological activity

Protein denaturation occurs when

-there is a change in pH or heat

-dehydration

-other stressors and detergents

Proteopathy diseases are those which are caused due to

protein misfolding

an example of a proteopathic disease

Alzheimer's