day 3 Flashcards
4 parts of an amino acid
amino group
side chain (R)
carboxyl group
alfa carbon
what bonds exist with a non-polar side chain (R)
london forces + hydrophobic interactions
what bonds exist with an UNCHARGED polar side chain (R)
hydrogen bonds + hydrophylic interactions + london forces
what bonds exist with a CHARGED polar side chain (R)
electrostatic attraction + hydrophylic interactions + hydrogen bonds + london forces
true/false: polypeptide chains (proteins) have directionality
TRUE
always have an amino group on one end (n-terminus) and a carboxyl group on the other end (c-terminus)
c-terminus
carboxyl group on end of polypeptide chain. new amino acids are added to this end of the chain
n-terminus
amino acid group on end of polypeptide chain. first amino acid that started the chain (new amino acids added to c-terminus)
primary structure
a sequence of amino acids linked by peptide bonds. always in the N-C-C order
secondary structure
local regions of polypeptide chains form 3D shapes. either alfa helix or beta sheet. formed by backbone interactions
2 types of secondary structures formed
alfa helix + beta sheet
tirtiary structure
final folding of polypeptide innitiated/involves mostly side chain (R) interctions
quaternary structure
only in multimeric proteins, the association between 2 or more peptides as they interact to form the final and functional protein
alfa helix formation
formed by hydrogen bonds between oxygen and hydrogen from seperate amino acids four units away on primary backbone
beta sheets
hydrogen bonds between oxygen + hydrogen on the primary backbone from adjacent regions forming rows (antiparallel or parallel)
chaperones
chaperones make polypeptide folding more efficient and reliable
2 ways chaperones work
- binding to partially folded chains
- form folding chambers
conformation
final 3D shape of polypeptide chain. determined by interactions between amino acids that forms the lowest free energy state
what 3 components can make up a tirtiary structure?
alfa helixes, beta sheets, random coils/unstructured regions
domain
segment of a polypeptide chain that folds into discrete and stable structure.
NOT the same as multimeric proteins
multimeric proteins
proteins made from more than one polypeptide chain which form ONE final functional protein
ligand
any substance bound by protein at a specific binding site
antibodies
bind antigens (ligands) at the interface of the heavy and light chains with high specificity
imunohistochemistry
detecting proteins (antigens) in cells or tissue using antibodies tagged with florescent labels.
demonstrates where a specific protein exists in a cell or tissue
substrate
ligand in an enzymatic reaction