Essay --

Part A: Describe protein structure, the level of structure and geometry. Include in a description of the significance of structure and how it affects to analysis. Protein Structure Levels There are four levels of protein structure which are separated from one another by the degree of complication in the polypeptide chain. A protein molecule can consist of one or more of the protein structure types. 1- ) Primary Structure is the sequence of a chain of amino acids. Proteins are formed from 20 different amino acids. Amino acid are composed of a carbon (ÃŽ ± carbon) that bond to the hydrogen atom (H), a carboxyl group (-COOH), an amino group (-NH2) and a variable group, or R group. The primary structure is determined during translation. There are two tools uses to determine the primary structure; Edman degradation and mass spectrometry. Primary structure controls the secondary, tertiary and quaternary structures. It is also used to determine the molecular mass and isoelectric point. 2- )Secondary Structure describes the coiling or folding of a protein due to exclusive hydrogen bonding between its backbone amide and carbonyl groups. These secondary structures are held together by hydrogen bonds. There are three types of secondary structures in proteins. a-) Alpha helix (ÃŽ ±-helix) is a spiral arrangement around polypeptide backbone. The inner part of the coil is formed by the backbone of the peptide while the side chains extend outward from the coil. Hydrogen bonds between N-H of one amino acid and the C=O on the 4th amino acid stabilize the helix. b-) Beta pleated the beta sheet involves H bonding between the backbone residues in adjacent chains. The orientation of a beta pleated sheet can occur in two types. The strands may be paralle... ...Da) than grw175 (28 kDa) proving that the above observation is true. b-) Molecular mass of the XÃ ¸D2788 gene product = 56 kDa 1.) Loaded the image of the gel into ImageJ 2.) Labeled the MW ladder lane then other lanes of interest (lane 2 grw175, lane 3 grw19) 3.) A graph representation was then generated 4.) I selected the peaks of MW lane to be used in the molwt.macros program 5.) Based on the calculations that were generated using the molwt macros program I was then able to select the peaks of interest and compute a numerical value for them 6.) ImageJ indicated a peak of 56kda for grw19 positive and a 28kda value in grw175 positive. 7.) Using the numerical values I was able to subtract the grw175 estimated size of 28kda from the size of what is believed to be the fusion protein grw19 56kda 8.) Grw175 = 28kda – fusion protein 56kda to give you a value of = 28kda