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Publication Abstract from PubMed

beta-N-Acetylgalactosamine-containing glycans play essential roles in several biological processes, including cell adhesion, signal transduction, and immune responses. beta-N-Acetylgalactosaminidases hydrolyze beta-N-acetylgalactosamine linkages of various glycoconjugates. However, their biological significance remains ambiguous, primarily because only one type of enzyme, exo-beta-N-acetylgalactosaminidases that specifically act on beta-N-acetylgalactosamine residues, has been documented to date. In this study, we identify four groups distributed among all three domains of life and characterize eight beta-N-acetylgalactosaminidases and beta-N-acetylhexosaminidase through sequence-based screening of deep-sea metagenomes and subsequent searching of public protein databases. Despite low sequence similarity, the crystal structures of these enzymes demonstrate that all enzymes share a prototype structure and have diversified their substrate specificities (oligosaccharide-releasing, oligosaccharide/monosaccharide-releasing, and monosaccharide-releasing) through the accumulation of mutations and insertional amino acid sequences. The diverse beta-N-acetylgalactosaminidases reported in this study could facilitate the comprehension of their structures and functions and present evolutionary pathways for expanding their substrate specificity.

Genetic and functional diversity of beta-N-acetylgalactosamine-targeting glycosidases expanded by deep-sea metagenome analysis.,Sumida T, Hiraoka S, Usui K, Ishiwata A, Sengoku T, Stubbs KA, Tanaka K, Deguchi S, Fushinobu S, Nunoura T Nat Commun. 2024 May 10;15(1):3543. doi: 10.1038/s41467-024-47653-2. PMID:38730244^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.