Transcript lecture03-2004.ppt

“Molecular
Workbenches”
Protein
function
Four levels of protein
Structure:
1°-aa sequence
2°-local folds/structure
3°-structure of polypeptide
4°-polypeptide interactions
cytochrome b
NAD-binding
antibody
Let’s make
glutamine from
glutamic acid
+
+
What are the energy
requirements?
How do we ensure
specificity?
DG = DH - TDS
G=free energy
H=enthalpy
S=entropy
T=temperature
Enthalpy is the energy
content of a molecule
DH=S bondsproducts-S bondsreactants
BOND
GLU
GLN
GLN-GL U
DH
C-C
C-O
C=O
C-H
N-H
O-H
C-N
4
2
2
5
5
2
1
4
1
2
5
4
3
2
0
-1
0
0
-1
1
1
TOTAL DH
0
-84
0
0
-93
110
70
3
Entropy is a measure
of disorder
DS=S disorderproducts
-S disorderreactants
The cell makes unfavorable
reactions proceed by
coupling them to
favorable reactions
Two modes of coupling:
Direct coupling
&
Sequential coupling
Sequential Coupling
A+B  C+D
D  E+F
Grand Challenges:
1. Given protein x,
determine its function.
2. Given function f,
determine the required
proteins.
Some numbers:
~30,000 humans genes
6
>10 including isoforms
~5,000 different
proteins/cell
>200 cell types
14
10 cells/body
Things that cells do:
divide
die
mutate
communicate
metabolize
D shape/move
specialize
learn
sense
store E
defend
Assay: A qualitative
or quantitative analysis
of a substance or
process.
Next Class
Nucleic Acids 101