Week 2 Flashcards
example of primary protein structure
AA sequence
what is a primary protein structure
a linear chain of amino acids
amino acids can be described as the __________ _______ of protein
building blocks
what part of the amino acid is variable
side-chain/r group
what determines the type of amino acid
the side chain/r group
name all components of an AA
amino group (NH2), carboxyl group (COOH), and side chain all attached to an alpha carbon
what are the 4 major categories of AA
acidic, basic, uncharged polar (ionization depends on pH of the solution that they are in), non polar
how many aa are there
20
where are non polar aa usually found
forms the inner core of proteins (eg pocket where a metabolite may bind) and often associated w lipid bilayer and membranes
where are uncharged polar aa usually found
usually on the outside of a protein
where are charged polar aa usually found
enzymatic functions and in charge of the shape of the protein
acidic r groups have a + or - charge
negative (side note, the also have the same first two nucleotides in the codon)
describe why is cysteine (aa) special
- strong cov bond
- non polar
- SH r group
- under correct conditions, you can form disulfide bond BETWEEN cysteines
- interchain for between and intrachain for within the aa
- the bonds happen bc of oxidation and removed due to reduction
why are disulfide bonds important for proteins
Disulfide bonds imp for proteins that are likely to undergo mechanical or chemical stress - eg proteins excreted outside a cell, sitting outside a plasma membrane, proteins in hair (curly) <== the ones that need to handle the stress
name the 2 classes of the secondary structure of protein
alpha helix and beta pleated sheets
describe peptide bonding
- Peptide bonds join the linear sequence/primary structure of protein
- rxn between carboxyl group and amino group - the OH and H makes water as a byproduct and a strong covalent peptide bond
- condensation rxn
- Strong and rigid, cannot rotate the atoms around this bond
what is a n and c terminus
the n terminus is the amino end of an aa and c terminus is the carboxyl end
in a polypeptide chain what is the polarity maintained by
Polypeptide chain completed and polarity maintained by distinct amino and carboxyl ends
when does an aa become an aa residue
once an aa is joined in a peptide bond
when are the terms carbonyl oxygen and amine hydrogen used
when aa are joined tgt in a peptide bond, the cooh is left with a c-o and the nh2 becomes a n-h
t/f is the shape of the protein important for how it binds to the receptor
yes
t/f do differences and order of aa matter in the sequence
yes