Download Explore the 3D Structure of Insulin

Explore the 3D Structure of Insulin
pdb101.rcsb.org
The Insulin hormone controls blood glucose levels. To learn more about the function of
insulin, visit pdb101.rcsb.org and read the Molecule of the Month on Insulin.
Primary Structure
To learn more about the primary, secondary, tertiary and quaternary levels of protein
structure, watch the What is a Protein? video at bit.ly/1JkBKgZ.
Cut out the five strips on the dotted line.
Make sure to separate the conjoined strips.
The green, orange, and yellow tabs have to
remain attached to their respective strips.
2. Protein Chains:
2.1. Chain A: Tape together the two pieces of the A
chain (green) so that residue 11 is back-to-back in
the two pieces, as shown in the picture.
Proteins are polymer CHAINS of amino
acid residues. Each number on the model
represents one amino acid residue.
2.2. Chain B: Tape together the three pieces of the B chain (blue) by overlapping the
gray tabs at the ends, so that all the numbers are visible on one side and all
the numbers are in order.
Insulin has 2 chains. Chain A is green;
chain B is blue.
Secondary Structure
1. Preparation:
3. Alpha Helices:
N-H and
C-O
groups
forming
hydrogen
bond
Hydrogen
bonds
Alpha Helix
Some sections of amino acid chains
curl and form ALPHA HELICES due
to HYDROGEN BONDS between N-H
and C-O groups.
The helix regions on the model are
marked on the chains with darker shades
of green and blue.
3.1. Chain A:
Starting with
residues 1 and 5
form a hydrogen
bond between
C-O and N-H, and
tape together.
3.4. Chain B:
Starting with
residues 7 and 11,
form a hydrogen
bond. Keep creating
the alpha helix until
you reach the end
of the darker
colored area.
3.2. Keep creating
the hydrogen bonds
until you reach the
end of the darker
colored area. When
you reach residue 6,
make sure the green
tab is on the outside
of the helix.
3.3. Create another
alpha helix starting
with residues 17 and
21. Keep creating
hydrogen bonds
until you reach the
end of the darker
colored area.
Turn
4. Turns:
Some amino acids give
a TURN to the chain.
The turns are marked
on chain B of the
paper model
with the white
dashed lines.
4.1. Fold outwards
on the white dashed
lines to create the
turns. You can
secure the folds
with tape.
Turn
Tertiary and Quaternary Structure
Note: Chain B also includes a beta strand marked with a blue arrow.
5. Disulfide Bridges:
The structure of Insulin is stabilized by
3 DISULFIDE BRIDGES. A disulfide
bridge is formed when a sulfur atom
from the residue cysteine forms a
single covalent bond with a sulfur
atom from a second cysteine.
5.1. The first disulfide bridge connects 2
5.2. Connect the yellow tabs, matching
cysteines in chain A. To form the bridge,
their shape while making sure the colored
connect the green tabs as seen on the photo. sides are facing the same way.
Complete model:
PDB ID 1trz
sulfur
Æ atom
The second and third disulfide bridges
(represented by orange and yellow tabs)
are formed between chains A and B.
Disulfide
Bridge
Æy
u
3D
5.3. Connect the orange tabs matching
their shape while making sure the colored
sides are facing the same way.
Go to pdb101.rcsb.org (Learn > Paper models) to DOWNLOAD
additional copies of this model, to watch a VIDEO DEMONSTRATION
of how to build it, and to access a DIGITAL ACTIVITY PAGE allowing for
further exploration of the 3D model.
PDB-101 is the educational portal of RCSB Protein Data Bank (rcsb.org)
N
H
28
N
H
27
N
H
26
N
H
25
O
C
15
24
O
C
N
H
N
H
14
23
O
C
N
H
N
H
13
22
O
C
N
H
N
H
12
21
O
C
N
H
N
H
11
N
H
10
N
H
N
H
8
N
H
N
H
7
O
C
1
N
H
CHAIN B
C
O
O
C
21
H
N
N
H
O
2
O
C
O
C
N
H
9
O
C
N
H
3
O
C
O
20
H
N
2
N
H
C
1
O
C
N
H
4
O
C
O
19
H
N
3
N
H
C
N
H
O
C
5
O
C
O
18
H
N
4
N
H
C
O
C
O
C
N
H
O
6
O
C
16
17
H
N
5
O
C
N
H
C
O
C
O
C
16
N
H
O
C
O
C
O
C
O
H
N
6
O
C
N
H
C
O
C
O
C
17
N
H
O
C
O
O
15
H
N
7
O
C
N
H
C
CHAIN A
O
14
8
H
N
O
C
O
C
N
H
C
PDB ID 1trz: E. Ciszak, G. D. Smith (1994)
Crystallographic evidence for dual coordination around zinc in the T3R3 human insulin
hexamer. Biochemistry 33: 1512-1517
O
C
18
N
H
O
C
11
12
13
C
N
H
9
H
N
O
C
N
H
10
H
N
O
C
N
H
11
O
C
C
The template for this paper model is based
on the human insulin structure (PDB entry
1trz, chains A and B).
#
rcsb.org
30
29
O
C
19
N
H
O
C
#
N
H
#
N
H
N
H
20
O
C
O
C
#
O
C
pdb101.rcsb.org
Explore the
3D Structure
of Insulin
PDB-101 is the educational portal of RCSB Protein Data Bank (rcsb.org)