Hemoglobin Lab Report

Haemoglobin is just one of the many possible forms and functions of a protein polymer. They all have different structures, which makes them specialised to carry out a particular function. For example enzymes. They are roughly spherical in shape due to the tight folding of the polypeptide chains. Enzymes play important roles in most biological processes, in particular metabolism and synthesis. The tertiary structure of an enzyme is of particular importance to its function and a slight change in the chain sequence and therefore it's shape can result in it becoming inactive. Enzymes work by combining with a substrate to form an enzyme-substrate complex, the substrate is then broken down and released. Each enzyme has a particular substrate that is can breakdown, this will be the substrate with the complimentary structure to that of the active site of the enzyme. For example starch is only broken down by amylase. As the shape of the active site depends on the shape of the polymer shape so does the over all function of the enzyme.

Different types of bonds/interactions in proteins lead to different kinds of structures. Three of the most commonly known chemical bonds in proteins include the hydrogen bond, the covalent bond, and the ionic bond. In hydrogen bonds, hydrogen interacts with oxygen, nitrogen, or fluorine to form either the alpha helix, or the beta sheet, which in turn determines its secondary, tertiary, or quaternary structure. Another type of bonds, the covalent bond, links amino acids together by sharing electrons;

The basic building blocks of proteins are amino acids, the biuret reaction tests for protein. A solution of sodium hydroxide is added to a sample then a few drops of copper sulphate solution, if positive – the solution will turn mauve. There are 20 different amino acids and they can be joined in any order. Therefore there can be many different functions. A protein consists of one or more polypeptide chains (a polypeptide chain being multiple amino acids joined together via condensation, producing a peptide bond). Different proteins have different shapes as the shapes are determined by the sequence of amino acids.

Proteins are important elements in cellular membranes and give the membranes many of their characteristics. In red blood cells, the meshwork of proteins in and around the membrane gives it strength and flexibility, allowing a cell to squeeze through small capillaries without bursting. Other proteins play roles in transporting material in and out of the cell (Lab Manual, Cell Biology). Polyacrylamide gel electrophoresis (PAGE), with all of its different modifications is probably the most widely-utilized procedure in contemporary biochemistry and molecular biology (Mordacq and Ellington (1994)). In this experiment, we will attempt to determine the molecular weights of the major proteins in the plasma membranes of bovine red blood cells (RBCs). The predictions made are if our protein has similar weights as proteins

A protein has multiple existing structures, these are the primary, secondary, tertiary and quaternary structures which occur progressively. A protein is essentially a sequence of amino acids which are bonded adjacently, and interact with one another in various ways depending on the R group that the amino acid contains. There are 20 different amino acids which are able to be arranged in any given order, thus giving rise to a potential 2.433x1018 (4.s.f) different combinations, and therefore interactions between the various amino acids.

addition, there seem to be several hydrogen bonds between the protein and the phosphate backbone of the DNA such as the oxygen in the phosphate group at position 33.

Proteins are made of amino acids, which are compounds built around a central carbon atom. Amino acids then join together through dehydration reactions. These are called peptide bonds. Many amino acids joined together are called polypeptides. A polypeptide becomes a protein when it folds into a three dimensional structure. This is the primary structure of a protein. The next structure in the hierarchy is the secondary structure. Secondary structures can either form alpha helixes, where an amino acid sequence forces the polypeptide to twist into a helical shape; or beta sheets, where an amino acid sequence forces the polypeptide into a zigzag shape. In the tertiary structure, the polypeptide folds several times on itself to form a more complex three dimensional shape. A quaternary structure is when two tertiary structures interact with each other. This is when a protein becomes a functional

For the second part of the experiment, one had to use the knowledge learn from viewing protein molecules in FirstGlance in Jmol to analyze the protein PDB ID: 4EEY. The analysis of this protein was done using the RSCB protein data bank (PDB) at (http://www.rcsb.org/pdb/home/home.do).2

There may also be sections where the secondary structure is neither helix nor sheet. Then the structure is called a random structure, indicating that it folds in random directions. The amino acids in an alpha helix are arranged in a right-handed helical structure resembling a spring. The alpha helix is the most common form of regular secondary structure in proteins. The beta-sheet is the second form of regular secondary structure in proteins consisting of beta strands connected laterally by three or more hydrogen bonds, forming a generally twisted, pleated sheet. The beta-sheet is sometimes called the beta pleated sheet since sequential neighboring atoms are alternately above and below the plane of the sheet giving a pleated appearance. Turns are the third of the three "classical" secondary structures that serve to reverse the direction of the polypeptide chain. They are located primarily on the protein surface and accordingly contain polar and charged residues. However, they are not very common in discussions of protein structure today.

The primary structure of a protein is the sequence of amino acids. This creates a polypeptide chain because each amino acid acts as a monomer so when they bind together they form a polymer. When amino acids bond together, a peptide bond is formed. This occurs when there is a condensation reaction and H2O is lost from the two amino acids and a bond forms between the carbon on one amino acid and the

23. Describe the structural-molecular biochemistry changes that occur in hemoglobin that occur when oxygen binds to hemoglobin

G-proteins are have three subunits, alpha (), beta () and gamma (), each composed of different amino acid therefore they are known as heterotrimeric. The G and G are tightly attached to each other so are known as the beta-gamma complex (G). G subunit has an important feature which is the binding site for exchange of GTP to GDP.

Yes, the change of the amino acid in the protein influences the overall structure. The healthy hemoglobin looks fairly spherical, with a few lumps on the surface. The Sickle Cell Anemia Hemoglobin looks like two identical, bumpy spheres were glued together to form one shape.

Bettelheim, Brown, Campbell and Farrell assert that polypeptide chains do not extend in straight lines but rather they fold in various ways and give rise to a large number of three-dimensional structures (594). This folding or conformation of amino acids in the localized regions of the polypeptide chains defines the secondary structure of proteins. The main force responsible for the secondary structure is the non-covalent

The experiment was done on the three varying types of hemoglobin molecules 1.carbonmonoxyhemoglobins, 2. Ferrohemoglobins with dithionite, and 3. Carbonmonoxyhemoglobins withdithionite ion. The difference between the first and third was to include a control group within these sub-experiments , and observing whether thionite affected the migration of the molecules in electrophoresis ( Pauling et al.,