View source for 1uj5

[[Image:1uj5.jpg|left|200px]]<br /><applet load="1uj5" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1uj5, resolution 2.00&Aring;" />
'''Crystal structure of Thermus thermophilus ribose-5-phosphate isomerase complexed with ribose-5-phosphate'''<br />

==Overview==
Ribose-5-phosphate isomerase (Rpi) acts as a key enzyme in the oxidative and reductive pentose-phosphate pathways for the conversion of ribose-5-phosphate (R5P) to ribulose-5-phosphate and vice versa. We have determined the crystal structures of Rpi from Thermus thermophilus HB8 in complex with the open chain form of the substrate R5P and the open chain form of the C2 epimeric inhibitor arabinose-5-phosphate as well as the apo form at high resolution. The crystal structures of both complexes revealed that these ring-opened epimers are bound in the active site in a mirror symmetry binding mode. The O1 atoms are stabilized by an oxyanion hole composed of the backbone amide nitrogens in the conserved motif. In the structure of the Rpi.R5P complex, the conversion moiety O1-C1-C2-O2 in cis-configuration interacts with the carboxyl oxygens of Glu-108 in a water-excluded environment. Furthermore, the C2 hydroxyl group is presumed to be highly polarized by short hydrogen bonding with the side chain of Lys-99. R5P bound as the ring-opened reaction intermediate clarified the high stereoselectivity of the catalysis and is consistent with an aldose-ketose conversion by Rpi that proceeds via a cis-enediolate intermediate.

==About this Structure==
1UJ5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with <scene name='pdbligand=5RP:'>5RP</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ribose-5-phosphate_isomerase Ribose-5-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.6 5.3.1.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UJ5 OCA]. 

==Reference==
Oxyanion hole-stabilized stereospecific isomerization in ribose-5-phosphate isomerase (Rpi)., Hamada K, Ago H, Sugahara M, Nodake Y, Kuramitsu S, Miyano M, J Biol Chem. 2003 Dec 5;278(49):49183-90. Epub 2003 Sep 17. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=13679361 13679361]
[[Category: Ribose-5-phosphate isomerase]]
[[Category: Single protein]]
[[Category: Thermus thermophilus]]
[[Category: Ago, H.]]
[[Category: Hamada, K.]]
[[Category: Kuramitsu, S.]]
[[Category: Miyano, M.]]
[[Category: Nodake, Y.]]
[[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]]
[[Category: Sugahara, M.]]
[[Category: Yokoyama, S.]]
[[Category: 5RP]]
[[Category: CL]]
[[Category: enzyme-substrate complex]]
[[Category: riken structural genomics/proteomics initiative]]
[[Category: rsgi]]
[[Category: structural genomics]]

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