Lecture 9 Flashcards
When is protein kinase c active
When it’s bound to the membrane and has calcium and DAG bound
what is the C2 region of protein kinase c made of an how does it help
It’s has a poly basic cluster of lysine residues that are postively charged
These lysine residues help it bind to the membranes negative charged phosphotidyl serine lipid heads
C1 and C2 domains of PKC binds what
C1A and C1B binds DAG
C2 binds the Phosphatidylserine and Phosphotidyl inositol lipid head groups (so the PIP2 groups) and calcium
To activate protein kinase C what domains have to be bound
The C1A or C1B (only need one bound to dAG to activate it)
The c2 to the membrane (Phosserine and PIP2)
What motif is in the c1 domains of PKC
The zinc finger motif
So it has two zinc ion (one in a and one in B)
Surrounded by 3 cysteine and 1 his each
What are the steps of PKC getting activated
DAG and ca are required
When ca, PKC goes to membrane, C2 domain binds pip2 and phosserine head groups
C1A or B bind DAG and the autoinhibitory site on PKC comes out (off)
The PKC is now active
What are the steps of PKC getting activated
DAG and ca are required
When ca, PKC goes to membrane, C2 domain binds pip2 and phosserine head groups
C1A or B bind DAG and the autoinhibitory site on PKC comes out (off)
The PKC is now active to activate other proteins involved in growth (because the kinase what activated by a growth factor)
What does PLC do
Once a GPCR is activated by a growth factor or other signal, the PLC is activated and cleaves PIP2 into DAG and IP3
This DAG binds to C1A of PKC to activate it
Why is magnesium in high concentrations in the cell (mM)
Because it is always bound to atp so it can stabilize the negative phosphate charge in atp
The amount of ato in the cell is also high, to mg would also have to be high
Is there free atp in cells
No since mg is always bound, mg-ATP is mostly what there is
To what phosphates is the mg in atp bound to
The beta (2nd) and gamma (3rd) phosphates
What is the coordination of mg when bound to the phosphates of atp
What does the mg bind to
Mg2+ so hard metal surrounded by oxygens, typically from water
octahedral geometry
Where else if magnesium found
In chrlorophyll
If magnesium isn’t bound to chlorophyll what happens
The absorbance of light from the sun changes, so red and blue light isn’t absorbed
It needs to absorb red and blue light for photosynthesis to happen and to make oxygen
Chlorophylls are a type of
Porphoryn (like hemoglobin)
Know how to draw general structure of chlorophyll
Slide 6
What is the exception of mg in chlorophyll and why
Mg2+ is a hard metal so it should bind to oxygen, but in chlorophyll it binds to nitrogen
This is because of the delocalized structure and electrons of chlorophyll surrounding it
What are the types of PTM in proteins
Phosphorylation
Ubiquitinations
Glycosylation
Methylation
Acetylation
Sumoylation
Sulfurylation
Fatty acylation (lipidation)
What do PTMS do
What is the evidence
they add groups to proteins to alter their function
When purified, proteins have modified amino acids (phosposerine, dimethylargenine)
What do PTMS do
What is the evidence
they add groups to proteins to alter their function
When purified, proteins have modified amino acids (phosposerine, dimethylargenine)
When can PTM happen
Cotranslationally (during translation)
Posttranslationally (after translation)
Are PTM specific or not
Yes specific, needs dedicated enzymes to doing the modification
Where to PTMS usually happen
How do they happen somewhere else
Usually on the surface of proteins
But if the modification is done cotranslationally and the protein folds, it can become internal
Are PTMS reversible
Yes
