Question

Describe in detail the primary, secondary, tertiary and quarternary structures of the Factor VIII molecule (anti-hemophilic factor)  

Answer 1

Factor VIII is a plasma protein which will correct the coagulation defect of patient with classical hemophilia.Its structure is three- dimensional arrangement of atoms in an amino acids chain molecule.

Primary structure:

The primary structure refer to the sequence of amino acids in the polypeptide chain.The primary structure is held togther by peptide bonds that are made during the process of protein biosynthesis.The two end of the polypeptide chain are referred to as the crboxyl terminus and the amino terminus based on the nature of free group on each extremity.This structure is determine by the gene corrosponding to the molecule..A specific sequence of nucleotide in DNA is transcribed into mRNA, which is read by the ribosme in a process called translation.Its sequence define its function.

Secondary structure:

The two main type of secondary strucure are alpha- helix or beta-sheet. The alpha-helix is a right handed coiled strand.The side chain substitute of amino acid groups in an alpha-helix extend to the outside.Hydrogen bond form between the oxygen of each C=O bond in the strand and the hydrogen of each N-H group four amino acids below it in the helix.The hydrogen bonding made this structure stable.The hydrogen bonding in a beta-sheet is a between strands rather than within strands.

Tertiary structure:

The overall three dimensional shape of molecule is the tertiary structure.The molecule will bend and twist in such a way as to acheive maximum stability or lowest energy state.Although the three dimensional shape of a protein may seen irregular and random,it is fashioned by many stabilizing forces due to bonding interavtions between the side-chain groups of the amino acids.

Quaternary structure:

Many molecule are made up of multiple polypeptide chains,often referred to as protein subunits.These subunits may be the same, as in homodimer.The quaternary structure refer to how these subunits interact with each other and arrange themselves to form a larger aggregate compolex.The final shape of the complex is once again stabilized by various interactions,including hydrogen-bonding,disulfide bridgs and salt bridges.