phosphodiester

Examples of phosphodiester in the following topics:

• DNA Replication in Prokaryotes

  • When the bond between the phosphates is broken, the energy released is used to form the phosphodiester bond between the incoming nucleotide and the growing chain.
  • It also requires a free 3'-OH group to which it can add nucleotides by forming a phosphodiester bond between the 3'-OH end and the 5' phosphate of the next nucleotide.
  • The nicks that remain between the newly-synthesized DNA (that replaced the RNA primer) and the previously-synthesized DNA are sealed by the enzyme DNA ligase that catalyzes the formation of phosphodiester linkage between the 3'-OH end of one nucleotide and the 5' phosphate end of the other fragment.

• DNA and RNA

  • The phosphate residue is attached to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′3′ phosphodiester linkage.
  • The phosphodiester linkage is not formed by simple dehydration reaction like the other linkages connecting monomers in macromolecules: its formation involves the removal of two phosphate groups.
  • A polynucleotide may have thousands of such phosphodiester linkages.

• The Structure and Sequence of DNA

  • In polynucleotides (the linear polymers of nucleotides) the nucleotides are connected to each other by covalent bonds known as phosphodiester bonds or phosphodiester linkages.
  • DNA has (a) a double helix structure and (b) phosphodiester bonds.

• Food Energy and ATP

  • ATP stores energy in phosphate ester bonds, releasing energy when the phosphodiester bonds are broken: ATP is converted to ADP and a phosphate group.

• DNA Repair

  • If an incorrect base has been added, the enzyme makes a cut at the phosphodiester bond and releases the incorrect nucleotide.
  • Once the bases are filled in, the remaining gap is sealed with a phosphodiester linkage catalyzed by DNA ligase .

• Initiation of Transcription in Prokaryotes

  • The A–T-rich -10 region facilitates unwinding of the DNA template; several phosphodiester bonds are made.

• Molecular and Cellular Cloning

  • Addition of an enzyme called DNA ligase permanently joins the DNA fragments via phosphodiester bonds.

• RNA Splicing

  • Once the introns are cleaved and removed, the exons are joined together by a phosphodiester bond.

• DNA Replication in Eukaryotes

  • However, DNA polymerase cannot catalyze the formation of a phosphodiester bond between the two segments of the new DNA strand, and it drops off.

• Basic Techniques to Manipulate Genetic Material (DNA and RNA)

  • To understand the basic techniques used to work with nucleic acids, remember that nucleic acids are macromolecules made of nucleotides (a sugar, a phosphate, and a nitrogenous base) linked by phosphodiester bonds.