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    Blunting is a process by which the single-stranded overhang created by a restriction digest is either "filled in", by the addition of nucleotides on the complementary strand using the overhang as a template for polymerization, or by "chewing back" the overhang, using an exonuclease activity. Vectors and inserts are often "blunted" to allow non-compatible ends to be joined. Sequence information is lost or distorted by doing this, and a detailed understanding of the modification should be sought before performing this procedure. Often, as long as the sequence being altered is not part of a translated region or a critical regulatory element, the consequence of creating blunt ends is negligible. Blunting a region of translated coding sequence, however, usually creates a shift in the reading frame. DNA polymerases, such as the Klenow fragment of DNA Polymerase I and T4 DNA Polymerase are often used to fill in (5´ → 3´) and chew back (3´ → 5´). Removal of a 5' overhang can be accomplished with a nuclease, such as Mung Bean Nuclease.

    1. DNA Blunting Tutorial

      The first step in determining how your ends will be blunted is to determine if they are 5´ or 3´ overhangs. This tutorial will teach you how to identify what type of overhang you have, as well as which enzyme will blunt that end, and how.

    Featured Products

    FAQs for Blunting

    Protocols for Blunting

    Common Applications of Exonucleases and Endonucleases

    NEB provides a list of common applications for our exonucleases and endonucleases.

    Properties of Exonucleases and Endonucleases

    NEB supplies many nucleases; several characteristics should be considered when choosing the one best suited to your particular research needs.