Sandbox wabash 07 Fumarase

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== Active Site Structure ==
== Active Site Structure ==
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The determined <scene name='72/726379/Active_site_a/1'>active site</scene> of fumarase involves ASN 141, THR 100, GLU 331, SER 98, HIS 188, ASN 326 and LYS 324. Amoung these residues, the most important one is HIS 188. In the fumarase active form, the imidazole ring of HIS 188 is oriented such that it forms a short hydrogen bond to a water molecule and GLU 331. GLU 331 may have contributed to increasing the basicity of HIS 188. This relay effect may in turn be passed to the active site water.It's worth noting that the current experimental data implies that HIS 188 does not interact directly with the <scene name='72/726379/C3_l-malate/1'>C3 position of L-malate</scene>, instead, it's the activated water molecule W-26 that removes the C3 proton of L-malate. HIS 188 has two functions in the catalytic process. First, it assists in binding the C4 carboxylate group of the substrate through Coulombic interactions.The C4 carboxylate of L-malate is the location of the double negative charge of the aci-carboxylate intermediate. The second function of HIS 188 is to activate W-26 to facilitate proton removal from the C3 position。 In this process, HIS 188 increases the basicity of the active site water molecule W-26. After C3 proton is moved to the water molecule, the extra Coulombic plus charge is close enough to aid in stabilization of the doubly negative charge present on the aci-carboxylate at C4.
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The determined <scene name='72/726379/Active_site_a/1'>active site</scene> of fumarase involves ASN 141, THR 100, GLU 331, SER 98, HIS 188, ASN 326 and LYS 324. Amoung these residues, the most important one is HIS 188. In the fumarase active form, the imidazole ring of HIS 188 is oriented such that it forms a short hydrogen bond to a water molecule and GLU 331. GLU 331 may have contributed to increasing the basicity of HIS 188. This relay effect may in turn be passed to the active site water.It's worth noting that the current experimental data implies that HIS 188 does not interact directly with the <scene name='72/726379/C3_l-malate/1'>C3 position of L-malate</scene>, instead, it's the activated water molecule W-26 that removes the C3 proton of L-malate. HIS 188 has two functions in the catalytic process. First, it assists in binding the <scene name='72/726379/C4_carboxylate_group/1'>C4 carboxylate group</scene> of the substrate through Coulombic interactions.The C4 carboxylate of L-malate is the location of the double negative charge of the aci-carboxylate intermediate. The second function of HIS 188 is to activate W-26 to facilitate proton removal from the C3 position。 In this process, HIS 188 increases the basicity of the active site water molecule W-26. After C3 proton is moved to the water molecule, the extra Coulombic plus charge is close enough to aid in stabilization of the doubly negative charge present on the aci-carboxylate at C4.
</StructureSection>
</StructureSection>
== References ==
== References ==
<references/>
<references/>

Revision as of 00:20, 29 February 2016

Fumarase Active Site

Fumarase

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References

  1. Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:http://dx.doi.org/10.1002/ijch.201300024
  2. Herraez A. Biomolecules in the computer: Jmol to the rescue. Biochem Mol Biol Educ. 2006 Jul;34(4):255-61. doi: 10.1002/bmb.2006.494034042644. PMID:21638687 doi:10.1002/bmb.2006.494034042644
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