Sandbox11: Difference between revisions

Acetylcholinesterase (AChE) is an monomeric enzyme.  Most often, AChE forms a tetramer and binds with a molecule, collagen Q, to connect to the membrane of the neuromuscular junction. <ref>http://www.ncbi.nlm.nih.gov/pubmed/11804574</ref>.  From the <scene name='Sandbox11/Secondary_structure/3'>secondary structure</scene>, it can be seen that there are 17 <scene name='Sandbox11/Alpha_helix_total/4'>alpha helices</scene> and 14 <scene name='Sandbox11/Beta_strands/3'>beta strands</scene>.  There  are 2 beta sheets formed from 3 anti-parallel and 11 anti-parallel beta sheets, respectively.  As the <scene name='Sandbox11/Original_structure/3'>overall tertiary structure</scene> shows, turns, alpha helices, and beta sheets all occupy a portion of the exterior of the protein.  The means that the turns must be composed primarily of polar side chains.  On the other hand, the alpha helices will be amphipathic with side chain order designated by the helical wheel;  the exterior will be filled with polar side chains that can hydrogen bond with water while the inside of the alpha helix will have nonpolar, hydrophobic groups.  The beta sheets must also be amphipathic, but the pattern of side chains is alternating polar and nonpolar.  In addition, in order to maintain its tertiary structure, the protein has three sulfide bonds, which are covalent bonds that form between cysteine residues.  The <scene name='Sandbox11/Disulfide_bond/3'>disulfide bond</scene> between cysteine 67 and cysteine 94 is 5.03 angstroms.