Structure of proteins II

Question 1

how are beta strands held together

Answer 1

interchain hydrogen bonding of the backbone C=O and N-H groups

Question 2

antiparallel beta sheets

Answer 2

adjacent strands run in opposite directions

Question 3

parallel beta sheets

Answer 3

adjacent strands run in same directions

Question 4

what are reverse turns stabilized by

Answer 4

hydrogen bonding, salt bridges, metal ions, disulfide bonds

Question 5

what is often found in reverse turns

Answer 5

proline and glycine

Question 6

what is tertiary structure

Answer 6

3D folded structure

Question 7

prosthetic groups

Answer 7

organic molecules that are permanently bound to the protein

Question 8

apoproteins

Answer 8

lack prosthetic group whilst the final functional molecule is said to have the native strucutre

Question 9

what is unqiue about myoglobin

Answer 9

has high affinity for oxygen
heme group contains an Fe2+ ion that is required for oxygen binding
secondary structural elements are all alpha helices

Question 10

what are some ways that the native structure of proteins can be denatured

Answer 10

incrased temp
detergents
pH extreme
agents like urea and guanidinium hydrochloride

Question 11

how does denaturing work

Answer 11

disrupt non-covalent bonds that maintain folded conformation of the protein

Question 12

how does protein foldign occur

Answer 12

favored pathways in a cooperative manner

Question 13

what is protein folding driven by in an aqueous environement

Answer 13

strong tendency of hydrophobic residues to be excluded from water

Question 14

forces that contribute to stabilizing protein structure

Answer 14

cystine disulfide bridges
hydrogen bonding
ionic interactions
hydrophobic forces

Question 15

where are salt bridges and hydrogen bonding usually taking place

Answer 15

internal portion of molecule or interfaces btwn polypeptide chains

Question 16

where are hydrophobic amino acids suually

Answer 16

interior

Question 17

prion

Answer 17

proteiancous infection partical

Question 18

examples of prion diseases

Answer 18

creutzfeldt jakob
kuru
vCJD

Question 19

how is kurur transmitted

Answer 19

funeral rites involving cannablism

Question 20

how is CJD spread

Answer 20

spontaneous and inherited

Question 21

how is vCJD spread

Answer 21

tranmitted

BSE-infected cow

Question 22

what secondary structure predominates in prions

Answer 22

beta sheet

Question 23

what aggregates in parkinsons

Answer 23

alpha synuclein

Question 24

Hb is a tetramer of what

Answer 24

2 alpha-globin and 2 b-globin subunits

Question 25

what does the Hb tetramer form form assocation of

Answer 25

2 alpha-beta dimers

Question 26

what are the cohesive forces acting in Hb

Answer 26

hydrophbic, hydrogen bonding, salt bridge

Question 27

when does Hb not bind O2 efficiently

Answer 27

low O2 conc

Question 28

where does Hb bind O2 efficiently

Answer 28

high O2 conc

Question 29

when does myoglobin bind O2 qwith high affinity

Answer 29

low O2

Question 30

what is the shape of Hb binding curve

Answer 30

sigmoid

Question 31

what is the shape of myoglobin binding curve

Answer 31

hyperbolic

Question 32

what is the tight conformation of deoxygenated Hb

Answer 32

T form

Question 33

what is happening during the T form

Answer 33

valine residue partially blocks the O2 binding site

Question 34

what is the high affinity Hb form

Answer 34

R-form

Question 35

how does 2,3 BPG affect Hb

Answer 35

stabilizes T form, reduces o2 affinity

Question 36

what happens when H+ bindings specific histdiines in Hb

Answer 36

form salt bridges, stabilizes T form, promotes O2 release