User:Cody Couperus/Sandbox 1: Difference between revisions

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Binding of thrombin by sodium or at exosite I stabilizes a form of thrombin that improves substrate recognition.<ref name='seven'/> This occurs due to energetic linkage between these sites to the S1 binding pocket and oxyanion hole. Rapid kinetic analysis suggests that thrombin is in a dynamic equilibrium that consists of a fast, slow, and inactive state<ref name='seven'/>. There is question as to the physiologic relevance of the inactive state. Regardless, there will be a proportion of fast:slow thrombin and sodium binding to the fast form stabilizes that conformation. Indeed, mutation of the residues involved in sodium binding diminishes the activity of thrombin.<ref name='seven'/> It should be restated, that current data suggest that sodium binding does not induce a conformation change, rather, it stabilizes a conformation of thrombin that has greater activity.

==Interesting Secondary Structure==

Thrombin has a <scene name='58/583418/Cis_proline/1'>cis peptide bond</scene> in a loop containing proline 37. The dihedral (Cα-C'-N-Cα) angle omega is 142.7 degrees.

[[Image:Capping.png|300px|right|thumb| “Capping box” motif in alpha thrombin (PDB: 1PPB) represented by His230 (Ncap) side chain and main chain hydrogen bonded with the backbone nitrogen of Arg233 (N3). An additional feature is a weak hydrophobic interaction between Thr229 (N’) and Val234 (N4) termed the “hydrophobic staple.” This motif derives it’s name from the box shaped hydrogen bonding pattern.]]

[[Image:Cation pi.png|300px|right|thumb| A cation-π interaction between Trp128 and Arg 129 in alpha thrombin (PDB: 2BDY). The guanidinium carbon is 3.6 angstroms from the top edge of the Trp. It is expected that the epsilon nitrogen forms the primary cation-π interaction. The electrostatic and Van der Waals interaction energies were calculated to be -3.29 kcal/mol and -3.08 kcal/mol respectively by the CaPTURE program (http://capture.caltech.edu/result.cgi).]]

</StructureSection>

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 Binding of thrombin by sodium or at exosite I stabilizes a form of thrombin that improves substrate recognition.<ref name='seven'/> This occurs due to energetic linkage between these sites to the S1 binding pocket and oxyanion hole. Rapid kinetic analysis suggests that thrombin is in a dynamic equilibrium that consists of a fast, slow, and inactive state<ref name='seven'/>. There is question as to the physiologic relevance of the inactive state. Regardless, there will be a proportion of fast:slow thrombin and sodium binding to the fast form stabilizes that conformation. Indeed, mutation of the residues involved in sodium binding diminishes the activity of thrombin.<ref name='seven'/> It should be restated, that current data suggest that sodium binding does not induce a conformation change, rather, it stabilizes a conformation of thrombin that has greater activity.
+==Interesting Secondary Structure==
+Thrombin has a <scene name='58/583418/Cis_proline/1'>cis peptide bond</scene> in a loop containing proline 37. The dihedral (Cα-C'-N-Cα) angle omega is 142.7 degrees.
+[[Image:Capping.png|300px|right|thumb| “Capping box” motif in alpha thrombin (PDB: 1PPB) represented by His230 (Ncap) side chain and main chain hydrogen bonded with the backbone nitrogen of Arg233 (N3). An additional feature is a weak hydrophobic interaction between Thr229 (N’) and Val234 (N4) termed the “hydrophobic staple.” This motif derives it’s name from the box shaped hydrogen bonding pattern.]]
+[[Image:Cation pi.png|300px|right|thumb| A cation-π interaction between Trp128 and Arg 129 in alpha thrombin (PDB: 2BDY). The guanidinium carbon is 3.6 angstroms from the top edge of the Trp. It is expected that the epsilon nitrogen forms the primary cation-π interaction. The electrostatic and Van der Waals interaction energies were calculated to be -3.29 kcal/mol and -3.08 kcal/mol respectively by the CaPTURE program (http://capture.caltech.edu/result.cgi).]]
 </StructureSection>