Introduction to protein structure Flashcards
what are the two properties binding is characterized into?
affinity
specificity
what does protein + carbohydrate give?
glycoprotein
what does protein + lipid?
lipoprotein
what is the structure of an amino acid?
what are the two main classes amino acids are put into?
hydrophilic and hydrophobic
what are hydrophilic amino acids classified as?
basic
acidic
polar
how do the two forms, anion and cation, of amino acids occur?
as pH decreases a H+ ion added to carboxylate
as pH increases a H+ removed form NH3+
what interactions do non-polar, aliphatic amino acids undergo?
hydrophobic
what interactions do polar, uncharged amino acids udnergo?
hydrophilic
why is the movement of the backbone of proteins prevented?
peptide bond is planar
what is the primary structure of the protiens?
‘linear sequence of amino acids’
secondary structure of proteins?
‘the localized organization of parts of a polypeptide chain’
e.g. alpha helix and beta pleated sheets dn connecting loops
tertiary structure of proteins?
3D structure of polypeptide chain
quaternary structure of protiens?
two or more polypeptide chains joined together
what is the structure of alpha helix?
cylindrical
H-bonding between carbonyl of first amino acid and fifth amino acid
proline doesn’t have an alpha helix
structure of beta sheets?
‘H-bonds between beta strands
run in parallel or anti-parallel
R-groups face up/down’
structure of teritiary strucutre?
covalent and non-covalent bonds
determined by amino acid sequence
different types of quaternary structures?
Homomeric and heteromeric
structure of quaternary structures?
hydrogen bonding and van der Waals
what do proteins fold into?
native conformation
where are hydrophobic and polar, charged residues buried?
hydrophobic in core of protein
polar/charged on water exposed surface
how are disulphide bridges formed?
covalent bonds formed between cysteine residue
intra and inter molecular bonding
formed under oxidizing conditions
what are domains?
‘distinct regions of proteins that function and fold independently and are functionally and structurally conserved’
what do functional domains do?
control certain activity of protein
what are structural domains for?
region of amino acids that form secondary and tertiary structures
what are structural motifs?
‘super-secondary structures that control similar function in different proteins’
what are the structural classes of protiens?
globular, fibrous, integral membrane
what are globular proteins?
high water solubility
compactly folded
included enzymes, transporters
what are fibrous proteins?
‘elongated proteins
low water solubility
large amounts of regular secondary structures’
what are integral membrane proteins?
associated with membranes
include hydrophobic amino acids
how are proteins related?
‘protein families are evolutionary related’
why is protein structure important for drug development?
aspirin covalently bonds to cyclooxygenase
how are proteins degraded?
difficult to access with protease for so ubiquitin-proteasome pathway used
then polyubiquitination
polyubiquitination recognised and unwinds secondary structure of ubiquitinated protein and hydrolyzes it
what are biomarkers used for?
to detect tissue damage
