5: protein structure

Question 1

is everything bt the side chains (amino-central a-carbon- carboxyl repeating)

Answer 1

polyptide backbone

Question 1

can be shown as both __ or ___
has a limtied ____ and is coplanar– N-C shares __ on the same ___
dipole exists– ___ IS + ___ IS -

Answer 1

trait of peptide backbone

single / double
rotation / e- / plane
O / amino

Question 2

is ama w/o side chain

Answer 2

residue

Question 3

primary vs secondary vs tertiary vs quarternary structure

Answer 3

1: sequence of ama residues; only 1 to not affected by denat
2: spatial arr. of a polyptide backbone, stabilized by H bonds (N-H and carbonyl)
3. 3D folding of a polypeptide, incoluding its side chains
4: spatial arr. of polyptideS IN PROTEIN, w/ multiple subunits

Question 4

proteins can be….

Answer 4

all a-helix
all bstrand
a & b
little to no 2nd strcutre

Question 5

proline causes a ___, destabilized by ____ (3.6 ama per turn)
side chains project in/outwards, a tightly packed core (w/ no space for __ )

Answer 5

kink / glycine
outwards water

THIS IS 2ND STRUCTURE: A-HELIX

Question 6

B-strand describe

Answer 6

B-pleated sheets. can be parallel or antiparallel (flips0
in antipaarallel, H bonds are straight -> more stable (paralel, curved)
bkhone are tally not straight on plane

Question 7

T or F

• urea can denat H bonds. affect all structures
  stronger than cov
  strongest when 3 atoms invovled are on striaght plane

Answer 7

• F. affect 2nd, tert, quat structures
  F-. ionic > cov > H bonds
  T

Question 8

to fold protein in tert strcutre

Answer 8

have 2 layers of 2nd struc: on top, a polar + charged regions exposed to aq solution
in inside, a hydrophobic core

Question 9

bonds in effect in tert structure

Answer 9

have noncov: ionic, van der waal and H bonds
cov disulfide bonds:
- btw cysteine residues in diff proteins
- can only form in oxidizing environment- extracellular is oxidizing (accepts e-)
to reverse, reduce

Question 10

bonds in quat structure e.g

Answer 10

same as tert strucutre e.g collagen and elastin
elastin fibre, when tied via cross links stretch
when exposed to H20, bcs hydrophobic, curl in
found in artery walls

Question 11

can protein move?

Answer 11

they aren’t completely rigid— domains can move , connnected via conform changes

Question 12

2 ways in which protein can fold with support

Answer 12

1) chaperone proteins guide the newly synthesized and partially folded into correctly folded
2) forms a vial (isolated space) -> proteins inside, chamber cap on top -> interact w/ side chain, correctly fold -> when done, dissociates

Question 13

denat occurs in: 6

Answer 13

extreme pH, high heat, alcohol and more slat
urea and guanidine hydrochloride can also denat protein

Question 14

how does cheese curd?

Answer 14

milk containse caseine protein
extreme pH denats it
precipitation curds cheese

Question 15

how does egg cook?

Answer 15

egg yt contains albumin
when exposed to heat, denat disulfide bonds
when tied via cross links, becomes stretched

Question 16

protein domain

Answer 16

a distinct region of a protein and can fold indepedently into compact structure
often functional units seprated from e/o cleft
connec via fleible regions
diff domain, duff function

Question 17

why do protein family exist and what is it?

Answer 17

during evolution, new protein come from old one
= a gorup of protein tht share a common evolutionary origin
similar sequence, function and domain

Question 18

residue neccessary for function are found within dowmain

Answer 18

conserved residue