Question

Which one of the following double-stranded sequences will NOT be recognized by a Type IIP restriction endonuclease?

• A. ( & 5'-GGTACC-3' )
  & 3'-CCATGG-5'
• B. ( & 5'-GGATCC-3' )
  & 3'-CCTAGG-5'
• C. ( & 5'-CATATG-3' )
  & 3'-GTATAC-5'
• D. ( & 5'-GAATTC-3' )
  & 3'-CTAAAG-5'
  end{tabular}

Hint:

When working with restriction endonucleases in molecular biology, always ensure to match the enzyme with its correct recognition sequence to achieve desired DNA modifications.

Answer 1

The Correct Option is D

Type IIP restriction endonucleases recognize specific palindromic DNA sequences and cleave within or near these sequences. Palindromes in DNA are sequences that read the same on both strands when oriented in opposite directions. 
Analysis of Each Option: (A) & (B): Both options A and B are palindromic sequences that are typical targets for Type IIP enzymes. For example, EcoRI recognizes 5'-GAATTC-3' (not shown as such here but similarly palindromic). 
(C): This sequence is also palindromic (reads the same forwards and backwards), commonly recognized by enzymes like NdeI. 
(D): The sequence shown in option D is not palindromic since the two strands do not read the same in the opposite direction, thus not likely recognized by a typical Type IIP restriction enzyme. Conclusion:
Explanation: Since Type IIP restriction endonucleases require a specific palindromic sequence to function, any non-palindromic sequence, such as the one shown in option D, will not be recognized or cut by such enzymes.