Proteins Flashcards
peptide bond formation is a ________ reaction
condensation.
water is eliminated
functional groups on an amino acid
central carbon connected to:
- nh2 - amine group
- cooh - carboxylic acid group
- r group
- h group
classification of amino acids
acidic basic neutral
hydrophobic hydrophilic
polar nonpolar
primary structure
amino acid number and sequence - PEPTIDE BONDS
secondary
local regions of pp chain. HYDROGEN BONDS between amino acid functional groups. alpha helice (0.54nm) and beta pleated sheets (0.7 nm)
tertiary
bonds between SIDECHAINS of amino acids. overall 3D conformation. hydrophobic core. polar aa side chains on the outside.
interactions: H BONDS, IONIC, VDW’s, DISULPHIDE bridges (by cysteine residues)
gives the general shape - globular, fibrous, membrane spanning etc.
quaternary
multi subunit complex.
eg. chloride transport for CFTR protein = membrane spanning
eg. o2 binding capacity of Hb = globular
cftr protein
Cystic fibrosis transmembrance conductance regulator protein
coded for by CFTR gene
cystic fibrosis
>1900 mutations found. most common deltaF508 mutation. class 2 mutations.
leads to misfolding of protein. largely retained in the ER, and degraded by the proteosome.
errors in the CFTR gene
structure: short/truncated proteins, misfolded proteins.
- leads to degradation / decreased stability / non functional / not trafficked to the membrane.
thalassemia
errors in Hb beta globin chain gene. can be:
-point mutations
-insertions
-base pair deletions.
lead to:
underproduction of beta globin chain of Hb
reduced B+ or absent B0 polypeptide chains.
point mutation - 3 types?
single base is changed.
silent = no effect missense = aa substitution nonsense = substitutes stop codon in place of an aa
frame shift mutations - 2 types?
insertions
deletions
inversion
inverts a segemnt of DNA end to end.
mutations, to affect protein synthesis, must occur in the __________ region of the DNA
coding
