Post-Exam 4 Material Flashcards
What are the 4 MAIN types of post translational modification?
1) Covalent Modification
2) Non-covalent Modification
3) Folding using chaperones
4) Ubiquitination
Modifications of the peptide bond are usually carried out by enzymes called
peptidases or proteases
Disulfide cross linking is a type of PTM involving the amino acid side chains. What is an example of this?
Process of preproinsulin being synthesized into insulin. Summary of this is after membrane transport the leader sequence is cut off (by protease) then the resulting proinsulin folds creating the disulfide bonds b/w cysteine’s lastly the connecting sequence is cleaved leaving mature insulin as the product.
Does proinsulin or insulin run faster on polyacrylamide gel?
Insulin because it is lighter in weight. Proinsulin will be at the top of the gel because it is heavier in weight.
________ is a form of PTM whenever the LYS in histone tail is added with acetyl coA and HAT to allow entry of enzymes for transcription.
Acetylation
_____ _______ anchors proteins into the cell membranes to the C terminus.
GPI Anchors
_________ is a form of PTM that is known in the example of vitamin C being needed in a reaction that takes Fe3+ to Fe2+
Hydroxylation
Enzymes that add on a PO4 group to an OH side chain are called
kinases
Enzymes that remove a PO4 group from a phosphorylated side chain are called
phosphatases
What protein is a kinase needed in EUK transcription?
TFIIH
What is the most abundant form of PTM?
Glycosylation
N lined glycosylation occur on ___ side chains because of the NH3 group.
ASN
O linked glycosylation occurs on ___ and ___ because the bond attaches to the OH group.
SER, THR
_____ attaches to the histidine group via Fe.
Heme
This is an example of a non covalent modification. It involves the ___ _____ domains used for DNA recognition example being the nuclear hormone receptors.
Zinc finger
_____ assits in protein folding
Chaperonin
______ is a type of PTM that is highly conserved. This involves its protein using it to degrade other proteins. This needs energy to function. It is the last form used to degrade proteins.
Ubiquitin
What is the protein that makes mRNA into cDNA?
reverse transcriptase
What are the basic steps in recombinant DNA experiment?
1) Preparation of DNA (vector and target DNA)
2) Cleavage of DNA in particular sequences (Restriction enzymes AKA endonucleases)
3) Ligation of DNA fragments (joining of the fragments)
4) Introduction of recombinant DNA into compatible host cells (genetic transformation)
5) Replication & expression of recombinant DNA in host cells
6) Identification of host cells that contain the recombinant DNA of intrest (Screening and selecting)
_____ are needed for reconstruction. They have to cut vector and pop in the target of gene to that region.
Endonucleases
_____ will join the target DNA to the plasmid
Ligase
What are plasmids?
independently replicating DNA “circles” (because PRO DNA). Foreign DNA can be inserted into the plasmid and replicated.
What are restriction enzymes?
cut DNA at highly specific regions AKA endonucleases
What do restriction enzymes recognize in nucleotides?
They recognize palindromic sequences which are inverted repeats
What is the best option to use for target DNA and why?
cDNA is the best option to use because it has an actual copy of the mRNA and it has NO introns
What is the process of cDNA preparation?
mRNA is converted into cDNA using reverse transcriptase, then there will be an attachment of oligo T’s to cDNA and the mRNA will be degraded. Next, a primer and polymerase will be added to make a copy of this cDNA to create a double stranded cDNA. This is what is used to insert into a plasmid.
What is the most common method in determining DNA sequences?
Dideoxy method AKA the sanger method
______________ are also known as chain terminators.
dideoxynucleotides
What will happen if you incorporate a dideoxy?
There will be an H in the 3’ position and that means it will stop transcription. There will be no attack and will NOT result in a phosphodiester bond.
What is the DNA sequencing procedure?
DNA sequence, primer, 4 normal dNTP’s (one of which is radioactively labeled for visualization). The mixture is then split among 4 test tubes. DNA poly is then added and synthesis begins. When these test tubes are then run through a gel, the smallest MW will be located on the bottom (5’ end) and the largest MW will be located on the top (3’ end).
