The QUATERNARY STRUCTURE

“A Structure Level Some Proteins Have”

The QUATERNARY STRUCTURE

The quaternary structure found in some proteins results from interactions between two or more polypeptide chains — interactions that are usually the same as those that give rise to the tertiary structure

The QUATERNARY Structure of Protein

•The Quaternary Structure of Protein is consist of two or more polypeptide chains and are held together by noncovalent interactions (hydrogen bonds, ionic bonds, and hydrophobic interactions)

•Subunits may either function independently of each other, or may work cooperatively, as in hemoglobin, in which the binding of oxygen to one subunit of the tetramer increases the attraction of the other subunits for oxygen.

The QUATERNARY Structure of Protein

Many proteins are made up of multiple polypeptide chains, often referred to as protein subunits.

The quaternary structure refers to how these protein subunits interact with each other and arrange themselves to form a larger combined protein complex.

The final shape of the protein complex is once again stabilized by various interactions, including hydrogen-bonding, disulfide-bridges and salt bridges.

Proteins with Quaternary Structure

Hemoglobin | Haemoglobin

Hemoglobin | Haemoglobin

•Hemoglobin, abbreviated Hb or Hgb, is the iron containing oxygen-transport metalloprotein in the red blood cells of all vertebrates as well as the tissues of some invertebrates.

•Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the rest of the body (tissues). There it releases the oxygen to permit aerobic respiration to provide energy to power the functions of the organism in the process called metabolism.

Proteins with Quaternary Structure

DNA Polymerases

The DNA PolymerasesThe DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule.

Every time a cell divides, DNA polymerase is required to help duplicate the cell’s DNA, so that a copy of the original DNA molecule can be passed to each of the daughter cells. In this way, genetic information is transmitted from generation to generation.

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