8xoc

beta-1,4-galacosyltransferase

spinqualitylabelsall models 8xoc, resolution 1.87Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8xoc is a 2 chain structure with sequence from Aggregatibacter actinomycetemcomitans NUM4039. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.87Å Ligands: GDU, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Lacto-N-neotetraose (LNnT), a representative oligosaccharide found in human milk, has been previously examined for its beneficial traits. However, the LNnT titer is limited by the efficient glycosyltransferase pathway, particularly with respect to the catalysis of rate-limiting steps. As data on the crystal structure of the key enzyme required for synthesizing LNnT are lacking, the synthesis of LNnT remains an uncertainty. Here, for the first time we report the three-dimensional structure of a bacterial beta-1,4-galactosyltransferase, Aabeta4GalT, and analyze the critical role played by residues in its catalytic efficacy. Guided by structural insights, we engineered this enzyme to enhance its catalytic efficiency using structure-guided tunnel engineering. The mutant enzyme L5 (K155M/H156D/F157W/K185M/Q216V) so produced, showed a 50-fold enhancement in catalytic activity. Crystal structure analysis revealed that the mechanism underlying the improvement in activity was of the swing door type. The closed conformation formed by dense hydrophobic packing with Q216V-K155M widened and permitted substrate entry. Our results show that altering the tunnel conformation helped appropriately accommodate the substrate for catalysis and provide a structural basis for the modification of other glycosyltransferases. Crystal structure and structure-guided tunnel engineering in a bacterial beta-1,4-galactosyltransferase.,Luo G, Huang Z, Zhu Y, Chen J, Hou X, Ni D, Xu W, Zhang W, Rao Y, Mu W Int J Biol Macromol. 2024 Nov;279(Pt 4):135374. doi: , 10.1016/j.ijbiomac.2024.135374. Epub 2024 Sep 10. PMID:39265897 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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