I. TRANSFORMING E. coli
with the pGREEN PLASMID
Carolina Biological Supply Co.
AP Biology Lab 6
#211082 ($102.00)
refill $21.50
II.
Purification of the GFP protein
#211072 ($45.25)
III. Electrophoresis of the GFP
protein #211073 ($87.25)
Purpose
Part 1 - To transform E. coli (plasmid contains
ampicillin resistance and green fluorescent
protein from Aequorea victoria (a bioluminescent
sea jelly))
Part 2 - To purify the GFP protein produced by
the newly transformed E. coli
Part 3 - To use electrophoresis to verify the
presence of the purified GFP protein.
Teacher Prep-Part I
• Pour LB agar plates, or prepare lab
to have students pour plates.
• Inoculate starter plates 24 hrs prior
to the lab
• Set up student stations.
• Set water bath to 42°C.
SUPPLIES
Group
Consumables
2
4
2
1
2
2
10 ul sterile loops
1-ml grad burel pipets (CaCl
transformation tubes
starter plate
Luria/ Amp plates
Luria plates
2
and mixing: feeding Luria broth: + cells: - cells)
1 vial CaCl 2 (3 ml)
1 vial luria broth (3 ml)
blue= replace after each period
red= keep on ice (turn in after each period)
blk= in group tray
Non-consumbles (Not included)
1
1
1
tray (for all equipmant)
ice bucket
marker
Class
water bath 42
ice
UV lamp
o
C
Background Information
1.
2.
3.
4.
5.
An understanding of the characteristics
and requirements of bacteria including
the effects of antibiotics.
An understanding of both natural and
artificial transformation in bacteria.
An understanding of genetic engineering
including the controversy. Excellent
opportunity to discuss/ debate bioethics.
Techniques: Use of sterile techniques
(TREAT ALL BACTERIA AS PATHOGENS),
burel pipet, little finger technique,
micropipet, and experience loading
electrophoresis gels.
Complete prelab: Make predictions about
outcome.
Procedure - Part I
Transformation
1.
Mark the 2 transformation tubes:+
2.
3.
Add 250 uL CaCl2 (ice cold) to each tube.
Using a sterile inoculating loop, add E. coli to each tube. MIX
WELL!!!
Using a new inoculating loop, add 1 loop of plasmid to + tube.
Incubate both tubes on ice for 15 minutes.
4.
5.
&-
Procedure - Part I
Transformation
6.
Label media:
7.
8.
9.
10.
11.
12.
13.
Procedure - Part I
Transformation
Heat shock the cells for 90 sec. Tubes should go directly
from ice to heat, and then directly back to ice.
Using the same burel pipet feed the cells in each tube
with 250 uL of Luria broth. (Best to feed - tube first)
Room/ body temperature 5 - 15 minute recovery period.
Using a new pipet transfer 100 uL of - cells to each of
the - plates.
Using a new pipet transfer 100 uL of + cells to each of
the + plates.
Spread the bacteria using the glass beads.
Clean up.
Results
• Plates without ampicillin (#1 & 2) will show
a “lawn” of growth: All materials needed
for growth are present without poison, so
bacteria will grow.
• Ampicillin plate without plasmid (#3):
Bacteria is killed - no growth.
• Ampicillin plate with plsamid (#4) will
show individual green (transformed)
colonies that glow under UV light: Only
bacteria that was transformed will grow;
therefore, the lesser growth will allow
individual colonies to be seen.
II. Purification of the GFP protein
#211072 ($45.25)
• Purpose: To purify the GFP protein
produced by the newly transformed
E. coli
Teacher Prep
1 day before lab
• Add ampicillin to Luria broth
• Prepare overnight cultures of GFP
expressing E. coli colonies (Taken from
Plate 4 of part 1 no more than 2 - 3 days
old) by inoculating 2 mL portions of Luria
broth w/ amp. Incubate at 33C (37C).
• Equilibrate the HIC bead resin.
• Set up student stations.
Supplies
• In Kit
• Needed
Background Information
• Using micropipets
Procedure - Part II
Purification of GFP by HIC
• Collect cells in pellet
Procedure - Part II
Purification of GFP by HIC
• Collect GFP Extract
from Cell Pellet
Procedure - Part II
Purification of GFP by HIC
• Collect GFP Extractfrom Cell Pellet
•
III. Electrophoresis of
the GFP protein #211073
($87.25)
Purpose: Part 3 - To use
electrophoresis toverify
the presence of the
purified GFP protein.
Teacher Prep
• Prepare tris-glycine SDS buffer
• Prepare a boiling beaker of water or a
water bath or heating block at 95C
• Aliquot protein marker in 7 uL
portions (1/ gel)
• Set up student workstation
Student Workstations
• 2 clean 1.5-mL microcentrifuge tubes
• students’ tube of purified GFP protein (on
ice)
• students’ tube of cell lysate (on ice)
• pipet and pipet tips (2–20 μL)
• permanent marker
• The following materials will be shared by every
two or three groups:
• 1 tube of protein markers (on ice)
• 12% polyacrylamide gel
• protein gel electrophoresis apparatus and power
supply
• 1x tris-glycine-SDS running buffer
• staining tray
• tube of 4ｰ— loading dye
• spatula for separating gel plates
• gloves
•
• Students will share the following:
• equipment for maintaining 95ｰC
• COOMASSIEｮ blue protein staining solution
• white light transilluminator (optional)
• instant or digital camera (optional)
Procedure
I. Denature Proteins, Load Gel, and Electrophorese (1 hour, 30
minutes)
• Note: There are 10 wells in each gel and each group will load
two samples, so each gel will be shared by two or three groups.
The protein markers also will be shared.
• 1. Place the 12% polyacrylamide gel into an appropriate gel
electrophoresis apparatus and add 1 x tris-glycine-SDS buffer
to both chambers. Remove the comb slowly and carefully.
Make sure that the sides of the wells are straight.
• 2. Use a permanent marker to label two 1.5-mL tubes:
• CL = cell lysate (from Part A, Step 9)
• GFP = purified GFP (from Part A, Step 16)
3. Transfer 5 μL of cell lysate (CL) and 15 μL of purified GFP
(GFP) into the appropriate tubes. These volumes correspond to
approximately 10 μg of total protein. Make sure that you have a
tube containing protein markers (PM).
• 4. Add 1.6 μL of 4ｰ— loading dye to tube CL. Add 5 μL of 4ｰ—
protein loading dye to tube GFP.
• 5. Heat the samples for two minutes at 95ｰC to denature the
proteins. Do not heat the marker. The marker sent with this kit
is formulated to be loaded without being heated.
• 6. Refer to Figure 1. Load 5μL of the protein marker into the
second well.
• Load the entire contents of each sample tube into a separate
well in the gel. Use a fresh tip to load each sample. Load
your samples in the following order from left to right: PM (5 μL),
CL (group 1), GFP (group 1), CL (group 2), GFP (group 2), CL
(group 3), GFP (group 3). Do not use the first and last lanes of
the gel, because bands from samples run in these lanes can
become distorted.
• 7. Close the tank of the protein gel
electrophoresis unit. Connect themelectrical
leads to a power supply, anode to anode and
cathode to cathode.
• Electrophorese at 175 volts until the
bromophenol blue band has moved to the bottom
of the gel. This should take approximately one
hour.
• 8. Turn off the power supply, disconnect the
leads from the inputs, and remove the top of the
electrophoresis box.
• 9. Carefully remove the gel cassette from the
electrophoresis chamber. Open the cassette with
a spatula and transfer the gel to a staining
tray.Wear gloves when you handle the gel.
Handle the gel with care to avoid tearing it.
• II. Stain the Gel with COOMASSIEｮ Blue, View, and
• Photograph (3+ hours)
• 1. Flood the gel with COOMASSIEｮ blue protein staining
solution, cover the staining tray to prevent evaporation, and
allow the gel to stain from one hour to overnight.
• 2. Wearing gloves, pour off the staining solution. Remove the
excess stain by rinsing the gel in tap water.
• 3. Destain the gel in tap water for one to two hours, changing
the water every 15 minutes. (The gel may also be destained
overnight in a small volume of water.) Protein bands will appear
blue. The longer the destaining period, the less intense the
background blue stain will appear. Do not destain for too long
or the protein bands may lose their intensity.
• 4. View the gel on a white background or on a white light
transilluminator.
• 5. Photograph the gel with an instant or digital camera
(optional).