structural proteins

structure/form--provide matrix for bone and connective tissue

dynamic proteins

provide transport, control of metabolism, contraction & chemical transformation

handedness of amino acids in human proteins

LEFT (rotate polarized light to the left)

peptide bond characteristics

like a double bond: no rotation about carbonyl carbon-nitrogen bond (planar)

*bonds around alpha carbon CAN rotate-->important in protein folding

Glutathione

most important agent that fights reactive oxygen species (by reducing them)

Glu-Cys-Gly

hydrophobic/ hydrophilic side chains and protein folding

hydrophobic (non-polar)-->interior-->stability

-->when clustered, act as ligand binding site

hydrophilic (polar)-->surface-->interactions with each other and water

mix of hydrophobic/philic-->increase salvation (stabilize protein in solution)

what holds subunits together in quaternary structure?

non-covalent associations

What handedness of alpha-helices do L-amino acids form?

right

alpha helix structure

hydrogen bonds between every 4th peptide bond

side chains project outward and are not involved in alpha helix hydrogen bonding

beta sheet structure

hydrogen bonds between adjacent chains

side chains project above and below and do not participate in beta sheet hydrogen bonding

secondary structure: random coils

unorganized

many are functional, part of binding sites or active centers

solubility of globular vs fibrillar proteins

globular: soluble in aqueous solutions

fibrillar: insoluble in aqueous solutions

advantages of quaternary structure formation

*stable (hydrophobic residues shielded from water)

*genetically economical--1 gene can code for complex protein

*efficient: substrate can react with several active sites in close proximity all at once

*cooperativity: subunit interactions can facilitate rxn

native structure

final conformation (most stable)

chaperones

protein family that assists in protein folding

part of HSP (heat shock protein) family--synthesis increased at higher tems to combat denaturation

4 important types of interactions in protein folding

1. disulfide

2. hydrophobic interactions

3. hydrogen bonds

4. ionic interactions

denaturation always-->

loss of function