9L8I
Rhodothermus marines cellobiose 2-epimerase RmCE in complex with mannobiose
Summary for 9L8I
| Entry DOI | 10.2210/pdb9l8i/pdb |
| Related PRD ID | PRD_900115 |
| Descriptor | Cellobiose 2-epimerase, beta-D-mannopyranose-(1-4)-beta-D-mannopyranose, CHLORIDE ION, ... (5 entities in total) |
| Functional Keywords | cellobiose 2-epimerase, complex, epimerization, isomerase |
| Biological source | Rhodothermus marinus JCM 9785 |
| Total number of polymer chains | 1 |
| Total formula weight | 47858.98 |
| Authors | |
| Primary citation | Saburi, W.,Muto-Fukiya, H.,Jaito, N.,Kato, K.,Yu, J.,Yao, M.,Mori, H. Biochemical and structural analysis of the mechanism for the catalysis and specificity of cellobiose 2-epimerase from Rhodothermus marinus. Biosci.Biotechnol.Biochem., 89:973-984, 2025 Cited by PubMed Abstract: Cellobiose 2-epimerase (CE) catalyzes C-2 epimerization of reducing end d-glucose/d-mannose residue of β-(1→4)-disaccharides, and also slightly catalyzes aldose-ketose conversion. In this study, we investigated the structure-function relationship of Rhodothermus marinus CE (RmCEs). In 2H2O, 2H replaced the 2-H of the reducing end sugar residue, suggesting a proton abstraction-addition mechanism via the cis-enediolate intermediate. The structure of the RmCE-mannobiitol complex showed that His259 was suitable for abstracting 2-H from d-mannose residue, whereas His390 was suitable for the d-glucose residue. H259A and H390A mutations abolished activity for Galβ1-4Man and Galβ1-4Glc formation from Galβ1-4Fru, respectively, and these mutants catalyzed both epimerization and isomerization to Galβ1-4Glc and Galβ1-4Man, respectively. Ala substitution of the residues interacting with the 2-O of the reducing end sugar residue significantly reduced the velocity for epimerization, but not for isomerization. Trp385, stacked onto the non-reducing-end sugar residues of disaccharides, was shown to be important for disaccharide specificity. PubMed: 40121185DOI: 10.1093/bbb/zbaf042 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.7 Å) |
Structure validation
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