What is the Difference Between T4 DNA Ligase and E Coli DNA Ligase?

T4 DNA ligase and E. coli DNA ligase are both enzymes that catalyze the formation of phosphodiester bonds between juxtaposed 5' phosphate and 3' hydroxyl groups in DNA. However, they have some key differences:

1. Source of Energy: T4 DNA ligase uses ATP as its energy source, while E. coli DNA ligase uses NAD.
2. Ability to Ligate Blunt Ends: Under normal reaction conditions, only T4 DNA ligase can ligate blunt ends of DNA fragments. E. coli DNA ligase, on the other hand, joins cohesive terminals produced by restriction enzymes.
3. Substrate Specificity: E. coli DNA ligase has a broader substrate specificity than T4 DNA ligase, making it useful for a wider range of applications.
4. Cofactor: E. coli DNA ligase uses NAD as a cofactor, while T4 DNA ligase does not.

In summary, T4 DNA ligase and E. coli DNA ligase differ in their energy sources, ability to ligate blunt ends, substrate specificity, and cofactor usage. These differences can impact their applications and efficacy in various molecular biology experiments and processes.

Comparative Table: T4 DNA Ligase vs E Coli DNA Ligase

Here is a table comparing the differences between T4 DNA Ligase and E. Coli DNA Ligase:

T4 DNA Ligase is an enzyme isolated from bacteriophage T4, while E. Coli DNA Ligase is an enzyme isolated from the bacterium E. coli. T4 DNA Ligase can join blunt ends of DNA fragments and is highly active, even at low concentrations. In contrast, E. Coli DNA Ligase requires cohesive terminals produced by restriction enzymes for ligation and uses NAD+ as a cofactor. T4 DNA Ligase has an optimal temperature of 16°C, while E. Coli DNA Ligase has a range of optimal temperatures from 4°C to 37°C.