Question

Put the following steps of the E. coli Nucleotide Excision Repair mechanism in order:

1. The repair enzyme complex recognizes and binds the distorted DNA.
2. The DNA is separated and SSB proteins bind and stabilize each strand.
3. Phosphodiester bonds on either side of the damaged DNA are cleaved.
4. The damaged DNA is removed.
5. DNA polymerase replaces missing nucleotides.
6. DNA ligase seals the nick at the 3' end of the newly synthesized DNA.

Answer 1

The correct order of the E. coli nucleotide excision repair mechanism includes recognizing and binding of the distorted DNA, cleaving phosphodiester bonds, stabilization of DNA strands with SSB proteins, removal of damaged DNA, synthesis of new nucleotides by DNA polymerase, and sealing the repaired DNA with DNA ligase.

Step-by-step explanation:

The E. coli nucleotide excision repair mechanism is a crucial process for correcting DNA damage, such as the formation of pyrimidine dimers due to UV exposure. The list provided contains the steps involved in this mechanism, and they need to be sequenced correctly to reflect how the process operates in cells.

1. The repair enzyme complex recognizes and binds the distorted DNA.
2. Phosphodiester bonds on either side of the damaged DNA are cleaved.
3. The DNA is separated, and SSB proteins bind and stabilize each strand.
4. The damaged DNA is removed.
5. DNA polymerase replaces missing nucleotides.
6. DNA ligase seals the nick at the 3' end of the newly synthesized DNA.

This sequence represents the orderly process by which E. coli cells can recognize and repair damaged DNA to maintain genetic integrity and prevent mutations.