Structural highlights
Function[MOSP_RUMA7] Catalyzes the phosphorolysis of beta-1,4-mannooligosaccharides to mannose 1-phosphate (Man1P) and shorter mannooligosaccharides. Can also catalyze the phosphorolysis of 4-O-beta-D-mannopyranosyl-D-glucopyranose (Man-Glc), but shows higher activity toward longer mannooligosaccharides. Involved in a mannan catabolic pathway which feeds into glycolysis.[1] Publication Abstract from PubMedIn Ruminococcus albus, 4-O-beta-d-mannosyl-d-glucose phosphorylase (RaMP1) and beta-(1,4)-mannooligosaccharide phosphorylase (RaMP2) belong to two subfamilies of glycoside hydrolase family 130. The two enzymes phosphorolyze beta-mannosidic linkages at the nonreducing ends of their substrates, and have substantially diverse substrate specificity. The differences in their mechanism of substrate binding have not yet been fully clarified. In the present study, we report the crystal structures of RaMP1 with/without 4-O-beta-d-mannosyl-d-glucose and RaMP2 with/without beta-(1-->4)-mannobiose. The structures of the two enzymes differ at the +1 subsite of the substrate-binding pocket. Three loops are proposed to determine the different substrate specificities. One of these loops is contributed from the adjacent molecule of the oligomer structure. In RaMP1, His245 of loop 3 forms a hydrogen-bond network with the substrate through a water molecule, and is indispensible for substrate binding. Structural insights into the difference in substrate recognition of two mannoside phosphorylases from two GH130 subfamilies.,Ye Y, Saburi W, Odaka R, Kato K, Sakurai N, Komoda K, Nishimoto M, Kitaoka M, Mori H, Yao M FEBS Lett. 2016 Mar;590(6):828-37. doi: 10.1002/1873-3468.12105. Epub 2016 Mar 4. PMID:26913570[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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