3wfz
From Proteopedia
Crystal structure of Galacto-N-Biose/Lacto-N-Biose I Phosphorylase C236Y Mutant
Structural highlights
FunctionLNPA_BIFL2 Reversibly phosphorolyzes lacto-N-biose to Gal1-P and N-acetylglucosamine (GlcNAc) and galacto-N-biose to Gal1-P and N-acetylgalactosamine (GalNAc). Involved in the lacto-N-biose I/galacto-N-biose (LNB/GNB) degradation pathway, which is important for host intestinal colonization by bifidobacteria.[1] [2] [3] Publication Abstract from PubMedGalacto-N-biose/lacto-N-biose I phosphorylase (GLNBP) is the key enzyme in the enzymatic production of lacto-N-biose I. For the purpose of industrial use, we improved the thermostability of GLNBP by evolutionary engineering in which five substitutions in the amino acid sequence were selected from a random mutagenesis GLNBP library constructed using error-prone polymerase chain reaction. Among them, C236Y and D576V mutants showed considerably improved thermostability. Structural analysis of C236Y revealed that the hydroxyl group of Tyr236 forms a hydrogen bond with the carboxyl group of E319. The C236Y and D576V mutations together contributed to the thermostability. The C236Y/D576V mutant exhibited 20 degrees C higher thermostability than the wild type. Directed evolution to enhance thermostability of galacto-N-biose/lacto-N-biose I phosphorylase.,Koyama Y, Hidaka M, Nishimoto M, Kitaoka M Protein Eng Des Sel. 2013 Sep 24. PMID:24065834[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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