Practice question

HindIII is a classic type II restriction enzyme widely used in NCERT textbook cloning illustrations and commercial vectors. It recognizes palindromic hexamer 5'-AAGCTT-3' and cuts between the two adenines on each strand, leaving four-base 5' overhangs AGCT that are cohesive and easily ligated. Recognizing sequence-specificity allows prediction of sticky end complementarity, calculation of fragment numbers after digestion, and design of compatible vectors like pBR322 which contains single HindIII site in tetracycline gene. Memorizing common palindromes including EcoRI GAATTC and HindIII AAGCTT is fundamental for solving restriction mapping problems.