1U26

Crystal structure of Selenomonas ruminantium phytase complexed with persulfated phytate

Summary for 1U26

• Entry DOI: 10.2210/pdb1u26/pdb
• Related: 1U24 1U25
• Descriptor: myo-inositol hexaphosphate phosphohydrolase, D-MYO-INOSITOL-HEXASULPHATE (3 entities in total)
• Functional Keywords: ptp, p-loop, phytase, hydrolase
• Biological source: Selenomonas ruminantium
• Total number of polymer chains: 2
• Total formula weight: 79152.60

Authors

Chu, H.M.,Guo, R.T.,Lin, T.W.,Chou, C.C.,Shr, H.L.,Lai, H.L.,Tang, T.Y.,Cheng, K.J.,Selinger, B.L.,Wang, A.H.-J. (deposition date: 2004-07-16, release date: 2004-11-09, Last modification date: 2024-03-13)

Primary citation

Chu, H.M.,Guo, R.T.,Lin, T.W.,Chou, C.C.,Shr, H.L.,Lai, H.L.,Tang, T.Y.,Cheng, K.J.,Selinger, B.L.,Wang, A.H.-J.
Structures of Selenomonas ruminantium Phytase in Complex with Persulfated Phytate; DSP Phytase Fold and Mechanism for Sequential Substrate Hydrolysis
STRUCTURE, 12:2015-2024, 2004

PubMed Abstract: Various inositide phosphatases participate in the regulation of inositol polyphosphate signaling molecules. Plant phytases are phosphatases that hydrolyze phytate to less-phosphorylated myo-inositol derivatives and phosphate. The phytase from Selenomonas ruminantium shares no sequence homology with other microbial phytases. Its crystal structure revealed a phytase fold of the dual-specificity phosphatase type. The active site is located near a conserved cysteine-containing (Cys241) P loop. We also solved two other crystal forms in which an inhibitor, myo-inositol hexasulfate, is cocrystallized with the enzyme. In the "standby" and the "inhibited" crystal forms, the inhibitor is bound, respectively, in a pocket slightly away from Cys241 and at the substrate binding site where the phosphate group to be hydrolyzed is held close to the -SH group of Cys241. Our structural and mutagenesis studies allow us to visualize the way in which the P loop-containing phytase attracts and hydrolyzes the substrate (phytate) sequentially.

PubMed: 15530366
DOI: 10.1016/j.str.2004.08.010

Experimental method

X-RAY DIFFRACTION (2.5 Å)