Random knowledge 1st test Flashcards
How many base pairs per turn of DNA helix
about 10
DNA helix is left or right handed
right handed
structural RNA
tRNA, rRNA, snRNA (small nuclear), snoRNA (small nucleolar RNA)
Regulatory RNA
miRNA (micro RNA), siRNA (small interfering RNA)
Information containing RNA
mRNA
Eukaryotic topoisomerase
Type I and II
And… what is the prokaryotice topoisomerase called?
Relieves torsional strain in replication
Type I: cuts 1 strand and moves
Type II: cuts both strands
Prokaryotic topoisomerase = gyrase
DNA Pol I
In prokaryotes
- distributive, no sliding clamp, slow
- replaces RNA primers
- does have proofreading (3’-5’ and 5’-3’)
DNA Pol III
Prokaryotic
- “processive” with sliding clamp, fast
- doesn’t remove RNA primer (no 5’-3’ exonuclease)
How to add 5’ cap (3 steps)
- Take off phosphate
- Add GTP backwards, remove 2 P -> GMP
- Methylate 7’ position
–> 5’ cap 7-methylguanosine
GU
conserved sequence beginning of intron (5’ part of intron)
take it off!
AG
conserved sequence end of intron (3’ end)
take it off!!!
consensus poly A initiation
AAUAAA
U1 snRNA
binds GU 5’ splice site
U2 snRNA
binds branch point A
U2 AF protein
binds AG 3’ intron spice site
Id protein
downregulate DNA binding. They are a member of Helix-Loop-Helix family and they dimerize (but they don’t have the necessary basic part of bHLH).
CREB modification
CREB + phosphorylization -> pCREB -> recruits CBP (which is a HAT) -> recruits RNA pol-II -> activates gene expression
prokaryotic IF’s
IF 1 and 3 bing 30S subunit bring it to RNA.
IF 2 brings formylmethionine
Alpha helix secondary structure
H bonds, turn = 3.6 residues (5.4 angstroms)
Fits well into dsDNA
H bonds formed between n and n+4
Collagen chain
individual chain is L handed, but 3 collagen chains form R handed triple helix
Collagen is proline and glycine rich
in connective tissue (tendons/cartilage/bone/cornea of eye)
keratin
in hair and nails
Kd
Kd = dissociation constant of protein-ligand
Kd= [ligand] at which 1/2 protein is bound
groEL
chaperone that encapsulates proteins to help them fold
Hsp70
chaperone that binds hydrophobic areas of proteins to prevent aggregation
prolyl isomerase
catalyze conversion trans/cis of proline
protein disulfide isomerase
catalyze disulfide formation between cysteins
