1sjb
From Proteopedia
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|PDB= 1sjb |SIZE=350|CAPTION= <scene name='initialview01'>1sjb</scene>, resolution 2.20Å | |PDB= 1sjb |SIZE=350|CAPTION= <scene name='initialview01'>1sjb</scene>, resolution 2.20Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> | + | |LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=OSB:2-SUCCINYLBENZOATE'>OSB</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= AAAR ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=37632 Amycolatopsis sp.]) | |GENE= AAAR ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=37632 Amycolatopsis sp.]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1sja|1SJA]], [[1sjc|1SJC]], [[1sjd|1SJD]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1sjb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1sjb OCA], [http://www.ebi.ac.uk/pdbsum/1sjb PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1sjb RCSB]</span> | ||
}} | }} | ||
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[[Category: Taylor-Ringia, E A.]] | [[Category: Taylor-Ringia, E A.]] | ||
[[Category: Thoden, J B.]] | [[Category: Thoden, J B.]] | ||
| - | [[Category: MG]] | ||
| - | [[Category: OSB]] | ||
[[Category: racemase]] | [[Category: racemase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:42:46 2008'' |
Revision as of 20:42, 30 March 2008
| |||||||
| , resolution 2.20Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Gene: | AAAR (Amycolatopsis sp.) | ||||||
| Related: | 1SJA, 1SJC, 1SJD
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
X-ray structure of o-succinylbenzoate synthase complexed with o-succinylbenzoic acid
Overview
Divergent evolution of enzyme function is commonly explained by a gene duplication event followed by mutational changes that allow the protein encoded by the copy to acquire a new function. An alternate hypothesis is that this process is facilitated when the progenitor enzyme acquires a second function while maintaining the original activity. This phenomenon has been suggested to occur in the o-succinylbenzoate synthase (OSBS) from a species of Amycolatopsis that catalyzes not only the physiological syn-dehydration reaction of 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate but also an accidental racemization of N-acylamino acids [Palmer, D. R., Garrett, J. B., Sharma, V., Meganathan, R., Babbitt, P. C., and Gerlt, J. A. (1999) Biochemistry 38, 4252-4258]. To understand the molecular basis of this promiscuity, three-dimensional structures of liganded complexes of this enzyme have been determined, including the product of the OSBS reaction and three N-acylamino acid substrates for the N-acylamino acid racemase (NAAAR) reaction, N-acetylmethionine, N-succinylmethionine, and N-succinylphenylglycine, to 2.2, 2.3, 2.1, and 1.9 A resolution, respectively. These structures show how the active-site cavity can accommodate both the hydrophobic substrate for the OSBS reaction and the substrates for the accidental NAAAR reaction. As expected, the N-acylamino acid is sandwiched between lysines 163 and 263, which function as the catalytic bases for the abstraction of the alpha-proton in the (R)- and (S)-racemization reactions, respectively [Taylor Ringia, E. A., Garrett, J. B, Thoden, J. B., Holden, H. M., Rayment, I., and Gerlt, J. A. (2004) Biochemistry 42, 224-229]. Importantly, the protein forms specific favorable interactions with the hydrophobic amino acid side chain, alpha-carbon, carboxylate, and the polar components of the N-acyl linkage. Accommodation of the components of the N-acyl linkage appears to be the reason that this enzyme is capable of a racemization reaction on these substrates, whereas the orthologous OSBS from Escherichia coli lacks this functionality.
About this Structure
1SJB is a Single protein structure of sequence from Amycolatopsis sp.. Full crystallographic information is available from OCA.
Reference
Evolution of enzymatic activity in the enolase superfamily: structural studies of the promiscuous o-succinylbenzoate synthase from Amycolatopsis., Thoden JB, Taylor Ringia EA, Garrett JB, Gerlt JA, Holden HM, Rayment I, Biochemistry. 2004 May 18;43(19):5716-27. PMID:15134446
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