5.1 Reversible Binding of a Protein to a Ligand: Oxygen-Binding Proteins

myoglobin

this facilitates oxygen diffusion in muscle tissue

hemoglobin

this is responsible for oxygen transport in the blood stream

prosthetic group

this is a non amino acid component that is part of a the structure of a protein

apoprotein

this a protein that does not have a prosthetic group

holoprotein

this a protein that has a prosthetic group

heme

iron in a prosthetic group is called a

poorly soluble diffusion

iron is needed to bind oxygen because O2 is ________ in aqueous solution and _____ is ineffective over long distances

myoglobin hemoglobin

heme is present in both ___ and ___

protoporphyrin

iron is in the middle of this ring structure

Kd

The dissociation constant is noted as

Ka

the association constant is noted as

[PL]/[P][L]

equation for Ka

[P][L]/[PL]

equation for Kb

Y

the fraction of protein printing sites that are occupied is given by this constant

[PL]/[PL]+[P]

equation for Y in ligand protein interactions

[L]/[L]+Kb

graphical equation for Y in ligand protein interactions

pO2/pO2+P50

equation for Y for oxygen bound to hemoglobin

R state

this state is when O2 has a higher affinity for hemoglobin

T state

the state is more stable when O2 is absent

O2 binding

this triggers hemoglobin to go from T state to R state

CO

this binds to hemoglobin better than O2

histidine

this distant amino acid increases hemes affinity for O2

allosteric

the binding of a ligand to one sit affects the binding properties of another site on the same portion

modulator

ligand that binds to a protein and revel a new shape / induce conformation change

homotropic

same ligand and modulator bind to allosteric site

heterotropic

modulator is a molecule other than the usual ligand

hemocytoblasts

what cells make red blood cells

not cooperative

if the slope of the hill plot is equal to one then ligand binding is _______

postive cooperatively

if the slop of the hill plot is greater than one them ligand binding is ________

negative cooperatively

If the slope of the hill plot is less than one then ligand binding is

decrease

Bohr effects states that has CO2 concentration increases and pH decreases, the affinity for O2 of hemoglobin will _______

N terminus

CO2 binds here in the peptide chain

decreases

2,3 BPG ______ the affinity of hemoglobin for oxygen

center

where does 2,3 BPG bind to hemoglobin

low

fetal hemoglobin has ____ affinity for 2,3 BPG

globin protein aggregation

hemoglobin S mutation causes this

hemoglobin S

Glu6 → Val6 is what mutation

Hemoglobin Hammersmith

Phe42 → Ser42 is what mutation

loss of heme binding

what is hemoglobin Hammersmith mutation

hemoglobin savannah

Gly24 → Val24 is what mutation

protein misfolding

what is hemoglobin savannah mutation

Hemoglobin milwaukee

Val67 → Glu67 is what mutation

loss of O2 transportation

what is hemoglobin Milwaukee mutation

hemoglobin kansas

Asn102 → Thr102 is what mutation

destabilizes R state

what is hemoglobin Kansas mutation

Hemoglobin Yakima

Asn99 → His99 is what mutation

destabilizes T state

what is hemoglobin yakima mutation

Hemoglobin Bibba

Leu136 → Pro136 is what mutation

destabilizes tetramer

what is hemoglobin bibba mutation

hemoglobin st lukes

Pro95 → Arg95 is what mutation

destabilizes tetramer

what is hemoglobin st Lukes mutation

Hemoglobin philadelphia

Tyr35 → Phe35 is what mutation

destabilizes tetramer

what is hemoglobin Philadelphia mutation