Amino Acids and Proteins Flashcards
structural or mechanical roles, polypeptides are intertwined to form cables or fibers
fibrous proeins
are functional or nonstructural, chains folded on itself to give compact rounded structure and are water soluble
globular proteins
aspartate is
acidic amino acid
glutamate is
acidic amino acid
arginine
basic
lysine
basic
histidine
basic
nonpolar
glycine, alanine, leucine and phenylalanine
serine, cysteine, threonine and tyrosine
neutral
glycine, alanine, leucine and phenylalanine
nonpolar
what forms of amino acid are found in humans
L forms
sulfur containing amino acids
methioine and cysteine
aromatic compounds
phenylalanine, tyrosine, and tryptophan
nonpolar
glycine, alanine, proline, valine, leucine, and isoleucine
polar
asparagine, glutamine, serine and threonine
2 cysteins can spontaneously oxidize to produce
cystine via a disulfide bridge
__________is a genetic disease resulting in defective transport protein that reabsorbs cystine into renal tubular cells and apppears in urine and forms calculi
cystinuria
_______is the sequence of amino acids in a polypeptide chain
primary structure
peptide bond is
carboxyl end and amino acid
__________is the folding or coiling of the chain to give regular repeated motifs
secondary structure
intramolecular H-bonding
between different parts of the same chain
intermolecular H bondingq
between different chains
how are secondary structures stabilized
stabilized by hydrogen bonds formed between the carbonyl oxygen of one peptide bond and the amino hydrogen of another
intermoleclar hydrogen bonding and intramolecular hydrogen bonding
beta pleated sheet
intramolecular hydrogen bonding
alpha helix
____________secondary structures is strong, non-elastic and flexible
beta pleated sheat
strong and may be elastic type of secondary structure
alpha helix
_______are strong rope like strucutres of intertwised alpha helices which are a major component of external protective layers in mammals
keratins
_______have high sulfur content and many S-S bonds
hard keratins
_______have low sulfur content and few S-S bonds between the chains
soft keratins
___________are a family of extracellular glycoproteins and are a major protein of connective tissue and forms insolbule fibers of great strength
collagnes
composition of collagens
rigid, cross linked triple helical rods
collagen has a high content of
glycine, proline, hydroxyproline and lysine
what two amino acids confer collagens rigidity
pro and hyp
what is the fundamental unit of collagen
tropocollagen
____________is a triple helical rod that is rigid and has a wider pitch than alpha helix to accomodate the bulky pro and hyp residues
collagen
________-is the modification of a structure after synthesis of the poypeptide chain
post-translational modification
_______ and ________ residues are hydroxylated
pro and lys
hydroxylated pro forms
h bonds between chains
hydroxylated lys forms
covalent bonds between chains
pro and lys residues become hydroxylated reuiqres
vitamin C
the collagen in tendons are arranged as
parallel bundles
the collagen in skin are arranged in
sheets of fibrils lyaered at many angles
the collagen in cartilage has
no distinct arrangement
cornea collagen is
planar sheats stacked corssways to minimize light scatter
_________is the overall 3d structure of the folded peptide
tertiary structure
globular proteins fold during and following synthesis along the same principles as
micell formation
what are some forces that can stabilize structures of globular proteins
electrostatic attractions
hydrogen bonds
hydrophobic interactions
disulfide bonds
________assist in protein folding by slowing it down to prevent inapprorpiate interactions
molecular chaperones
_____________are protein conformational diseases caused by misfolded proteins
prion diseases
what protein structure is messed up in prion diseases
tertiary structure
_____________are domains that are physically independent regions within the overall tertiary structure of a large complex protein
structural domains
polymorphisms, protein families isoforms, and developmental variation are all examples of
variations in primary structure
_____________ are variations in primary structure of 2 or more alleles may be silent some have a profound effect
polymorphisms
_________-are proteins with simila but NOT identical structure and function that have evolved from the same ancestral protein; sequences very similar
protein families
examples of protein families
hemoglobin chains, myoglobin serine proteases
_____________perform essentially the same function and are highly homologus and evolved from the same ancestral gene possess different amino acid sequences and physico-chemical properties
protein isoforms
___________are different isoforms that are expressed during different stages of development
developmental variation
__________are highly similar sequences that evolved from the same ancestor
homologs
____________are from different species but orignated from same gene in ca common ancestor and normally retain same function
orthologs
example of orthologs
human bovine and procine insulin
___________from same species, originated from common ancestral gene, have different functions ( myogloin and different hemoglobin chains)
paralogs
fetal hb have what structure
alpha 2 gamma 2
adult hb have what structure
alpha 2 beta 2 or alpha 2 delta 2
gower I
zeta 2 epsiolon 2
gower II
alpha 2 epsiolon 2
protalnd I
zeta 2 gamma 2
________is the aggregation of an interaction between subunits in a multimeric protein
quatenary structure
human hemoglobin differences are examples of
paralogs
does myoglobin have a higher or lower affinity for oxygen
myoglobin
in the absence of oxygen hemoglobin is predominantly in the
T state
when oxygen binds all four subunits change to the ________ state
R state
binding of myoglobin is
noncooperative so graph is hyperbolic
at a lower pH Hb has a
less affinity for the oxygen
fetal red blood cells have
higher affinity for oxygen than maternal RBC’s
2,3 BPG and carbon dioxide both
decrease hb affinity for oxygen
when proteins denature the structures is lost but
primary structure remains in intact
