Sandbox108: Difference between revisions

 
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{{STRUCTURE_2gls |  PDB=2gls  |  SCENE=  }}
{{STRUCTURE_2gls |  PDB=2gls  |  SCENE=  }}


== OUTLINE ==
 


''Glutamine synthetase of Salmonella typhimurium''
''Glutamine synthetase of Salmonella typhimurium''




Tertiary structure of protein is characterized by the “global” folding of a polypeptide chain [http://www.stanford.edu/group/pandegroup/folding/education/prstruc.html] and has two domains in refined atomic model of glutamine synthetase from Salmonella typhimurium. Hydrophobic interaction is a major driving force determining the most tertiary structure of the proteins. [http://www.stanford.edu/group/pandegroup/folding/education/prstruc.html] Hydrogen bonding is crucial in stabilizing the tertiary structure as well. [http://webhost.bridgew.edu/fgorga/proteins/proteins.htm] Also, disulfide bonds between cysteine residues stabilize the tertiary structure. [http://webhost.bridgew.edu/fgorga/proteins/proteins.htm] However, for glutamine synthetase for Salmonella, the most important interaction will be the helix-helix interactions.  
 
Tertiary structure of protein is characterized by the “global” folding of a polypeptide chain [http://www.stanford.edu/group/pandegroup/folding/education/prstruc.html] and mostly affected by <scene name='Sandbox108/Hydrophobic/1'>Hydrophobic(purple)</scene>(<scene name='Sandbox108/Polar/1'>polar(blue)</scene>) interaction and hydrogen bonding. In general, hydrophobic interaction is a major driving force determining the most tertiary structure of the proteins. Hydrogen bonding is crucial in stabilizing the tertiary structure as well.[http://webhost.bridgew.edu/fgorga/proteins/proteins.htm] Also, disulfide bonds stabilize the tertiary structure in residues such as cysteine residues.[http://webhost.bridgew.edu/fgorga/proteins/proteins.htm] However, for Salmonella typhimurium it is mostly influenced by the helix-helix interactions between 12-subunits enzymes within two layers.[http://www.stanford.edu/group/pandegroup/folding/education/prstruc.html]




Glutamine synthetase from Salmonella typhimurium has 23 helix-helix interactions involving helices of chain A and four different types of interactions. [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl?pdbcode=2gls&template=protein.html&o=HELIX_INTERACTIONS&l=1&s=1&c=7&chain=A] Helix-helix interactions are the only interaction that can affect the folding of the proteins in Salmonella typhimurium. <scene name='Sandbox108/Hydrophobic/1'>Hydrophobic(purple)</scene> and <scene name='Sandbox108/Polar/1'>polar (blue)</scene> regions of the protein residues are on the helices of chain A. Also, uncharged polar groups are usually classified as hydrophilic that is found on the outside of proteins, but for glutamine in Salmonella typhimurium its side chain is uncharged and formed by replacing the hydroxyl of glutamic acid with an amine functional group. [http://en.wikipedia.org/wiki/Glutamine] Moreover, on the helices of chain A has <scene name='Sandbox108/Charged_region/1'>the charged regions</scene>.
Glutamine synthetase from Salmonella typhimurium is the 12-subunits enzyme, and has 23 helix-helix interactions involving helices of chain A with four different types of interactions. [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl?pdbcode=2gls&template=protein.html&o=HELIX_INTERACTIONS&l=1&s=1&c=7&chain=A] The 12-subunits enzyme are arranged in two layers of six, such as <scene name='Sandbox108/Glu_131/1'>Glu-131</scene> which is the one of the protein residues of Salmonella typhimurium; at the interface of pairs of subunits within each layer, six anti-parallel beta strands formed cylindrical active sites.[http://www.ncbi.nlm.nih.gov/pubmed/2572586?dopt=Abstract] Each active site holds two <scene name='Sandbox108/Mn/3'>Mn2+</scene> ions surrounded by some <scene name='Sandbox108/Histidyl_side_chain/1'>histidyl side chains.</scene> [http://www.ncbi.nlm.nih.gov/pubmed/2572586?dopt=Abstract] Also, the protein ligands to Mn2+ 469 are <scene name='Sandbox108/Glu_131/3'>Glu-131</scene>, <scene name='Sandbox108/Glu_212/3'>Glu-212</scene>, and <scene name='Sandbox108/Glu_220/2'>Glu-220</scene>; those to Mn2+ 470 are <scene name='Sandbox108/Glu_129/2'>Glu-129</scene>, <scene name='Sandbox108/His_269/1'>His-269</scene>, and <scene name='Sandbox108/Glu_357/2'>Glu-357</scene>.[http://www.ncbi.nlm.nih.gov/pubmed/2572586?dopt=Abstract] Glutamine from Salmonella typhimurium has 12-subunits of each of them in pairs within two layers. C-terminus end of the polypetide and a helical thong, which inserts into a <scene name='Sandbox108/Hydrophobic/1'>Hydrophobic(purple)</scene> pocket formed by two neighboring subunits on the opposite ring, hold the two layers of subunits tightly.[http://www.ncbi.nlm.nih.gov/pubmed/2572586?dopt=Abstract] Also, <scene name='Sandbox108/Hydrogen_bonded_beta-sheet/1'>hydrogen-bonded beta sheet interactions(black)</scene> can affect the form of tertiary structure, but <scene name='Sandbox108/Hydrophobic/1'>Hydrophobic(purple)</scene> interactions will contribute to the stability of the intersubunit between two layers more efficiently.[http://www.ncbi.nlm.nih.gov/pubmed/2572586?dopt=Abstract] In the other hand, the most effective interaction in glutamine synthetase from Salmonella typhimurium is the helix-helix interactions. The folding of the proteins can be affected by the 12-subunits in the residues. In the case of Salmonella typhimurium the helices of chain A has <scene name='Sandbox108/Charged_region/1'>the charged regions(blue and red)</scene>, while most glutamine has uncharged side chain which formed by replacing the hydroxyl of glutamic acid with an amine functional group. Moreover, glutamine from Salmonella typhimurium has two domains; "beta-grasp domain" and "catalytic domain."[http://www.ncbi.nlm.nih.gov/Structure/cdd/cddsrv.cgi?uid=pfam03951][http://www.ncbi.nlm.nih.gov/Structure/cdd/cddsrv.cgi?uid=pfam00120] In short, this is N-terminal and C-terminal domain.[http://www.rcsb.org/pdb/explore/explore.do?structureId=2GLS] The N-terminal domain refers to the end of a polypeptide which has a free amine group,[http://en.wikipedia.org/wiki/N-terminal_domain] and the C-terminal end of the polypeptide has a free carboxyl group.[http://en.wikipedia.org/wiki/C-terminus] As a result, glutamine synthetase for Salmonella typhimurium depends mostly on the helix-helix interactions involving helices with four different types of interactions. 12-subunits enzymes are arranged in two layers of six, where the hydrogen-bonded beta sheet and hydrophobic interactions occur.

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