3VNI

Crystal structures of D-Psicose 3-epimerase from Clostridium cellulolyticum H10 and its complex with ketohexose sugars

Summary for 3VNI

• Entry DOI: 10.2210/pdb3vni/pdb
• Related: 3VNJ 3VNK 3VNL 3VNM
• Descriptor: Xylose isomerase domain protein TIM barrel, MANGANESE (II) ION (3 entities in total)
• Functional Keywords: d-psicose 3-epimerase, ketohexose, isomerase
• Biological source: Clostridium cellulolyticum
• Total number of polymer chains: 4
• Total formula weight: 132809.39

Authors

Chan, H.C.,Zhu, Y.,Hu, Y.,Ko, T.P.,Huang, C.H.,Ren, F.,Chen, C.C.,Guo, R.T.,Sun, Y. (deposition date: 2012-01-16, release date: 2012-08-01, Last modification date: 2023-11-08)

Primary citation

Chan, H.C.,Zhu, Y.,Hu, Y.,Ko, T.P.,Huang, C.H.,Ren, F.,Chen, C.C.,Ma, Y.,Guo, R.T.,Sun, Y.
Crystal structures of D-psicose 3-epimerase from Clostridium cellulolyticum H10 and its complex with ketohexose sugars.
Protein Cell, 3:123-131, 2012

PubMed Abstract: D-psicose 3-epimerase (DPEase) is demonstrated to be useful in the bioproduction of D-psicose, a rare hexose sugar, from D-fructose, found plenty in nature. Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase. In this study, the crystal structure of the C. cellulolyticum DPEase was determined. The enzyme assembles into a tetramer and each subunit shows a (β/α)(8) TIM barrel fold with a Mn(2+) metal ion in the active site. Additional crystal structures of the enzyme in complex with substrates/products (D-psicose, D-fructose, D-tagatose and D-sorbose) were also determined. From the complex structures of C. cellulolyticum DPEase with D-psicose and D-fructose, the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues. Accordingly, based on these ketohexose-bound complex structures, a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here. These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis.

PubMed: 22426981
DOI: 10.1007/s13238-012-2026-5

Experimental method

X-RAY DIFFRACTION (1.98 Å)