Question

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

Answer 1

Factor VIII molecule is a blood clotting protein.

Primary structure of factor VIII

a)FVIII -FL- single chain domain organisation.The three acidic domain a1, a2,a3 important for FVIII proteolytic activastion by THrombin,indicated dark grey boxes FVIII is a mixture of heterodimers of non-covalently linked heavy chain of the A1-A2-B domais and light chain of the A3-C1-C2.FVIIII -BDD-SC andFVIII- BDD hetrodimer lacking the B-domain.

b)PAA SDC gel of VIII st indicate the moleculer weight of the standards in kDa. C) Amino acid sequence alignment between hFVIII -FLat the A2a2 a3A3 level showing the 14 and 24 amino acid and linkers introduced for human and porcine FVIII-BDD forms,respectively.

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.