Sandbox 50

Please do NOT make changes to this Sandbox. Sandboxes 30-60 are reserved for use by Biochemistry 410 & 412 at Messiah College taught by Dr. Hannah Tims during Fall 2012 and Spring 2013. spinqualitylabelsall models Insert caption here Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image TrypsinTrypsin Trypsin is a medium sized, globular, digestive serine protease that is synthesized by the pancreas and secreted into the duodenum of the small intestine. Trypsin hydrolyzes peptide bonds based on side chain specificities of the amino acids surrounding the bond to be cleaved. Trypsin's specificity is for the positively charged side chains of lysine and arginine. StructureStructure Trypsin's primary structure is a polypeptide chain of 237 amino acids. These amino acids interact with each other mostly through hydrogen bonding to form trypsin's secondary structural units. Trypsin has many important , including two alpha helices (blue), an anti-parallel beta sheet (green), and random coils (gray). The arrows on these elements point toward the carboxy terminus of the protein. These secondary structures interact together to form the fully folded, native trypsin. Polar and Nonpolar ResiduesPolar and Nonpolar Residues Trypsin's distribution of follow the rules of the hydrophobic effect. The nonpolar (gray) residues are located on the interior of the protein so they can be shielded from water, while the polar (purple) residues are distributed on the exterior of the protein because they can interact with water. This model shows the distribution of the hydrophilic and hydrophobic residues and the actual space they occupy. Again the hydrophobic, nonpolar residues are shown in gray, and the hydrophilic, polar residues are purple. This type of residue distribution in trypsin is entropically favorable becuase the water surrounding the protein does not become ordered. Attractions Between Structural Components and the Remainder of the ProteinAttractions Between Structural Components and the Remainder of the Protein Disulfide BondsDisulfide Bonds Trypsin contains three involving six cysteine residues. These disulfide bonds are intramolecular forces that stabalize the tertiary structure of Trypsin. The figure shows the yellow disulfide bonds between the cysteine residues connecting two random coils, connecting one of the alpha helices to the beta sheet, and the other disulfide connecting the two alpha helices. Residue ChargeResidue Charge This -charge figure- shows the different charges of the amino acid residues that make up Trypsin. The blue residues have cationic side chains, the red residues have anionic side chains, the light purple are the polar, uncharged residues, and the gray residues are hydrophobic. When compared to the spacefilled figure above, the direct correlation between polarity of the side chain and charge of the side chain can be seen. Those residues with charged (blue and red) side chains as well as the polar, uncharged residues are the residues on the exterior of the protein, while the hydrophobic residues remain at the protein's core. Those residues that are cationic and anionic are able to participate in salt bridges. Ligand ContactsLigand Contacts