Checking our ligases

Since our ligation experiments didn't work during these few days, we presume that our problem came from the ligases. That's why we decided to check the activity of the ligases in our possession. To do so:

• we will digest a plasmid with only one restriction enzyme (EcoRI).
• then we will try to ligate it back using our ligases.

Condition tested

Before gel excision
well n°4: undigested plasmid (MP101.1)
well °6, 7, 8, 9: digested plasmid (D202)

After gel excision

After purification

Digestion

Reaction mixture (carried out four times )

• ADN (MP101.1): 3.8 µL
• H2O: 21.9 µL
• 10X Buffer: 3 µL
• BSA: 0.3 µl
• EcoRI: 1 µL

Purification

• We purifed our digestion products by gel extraction (Qiagen kit)
• After elution, we obtained [DNA] = 25 ng/µL (based on the intensity of the band)

Overnight ligation (16°C)

• DNA: 4 µL
• 10X Buffer: 2 µL
• Ligase: 1 µL
• H2O: 13 µL