{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Fucose mutarotases—commonly referred to as FucU (or FucM in some mammalian contexts)—comprise a conserved family of proteins that facilitate the interconversion of the α‐ and β‐anomers of L‐fucose, thereby optimizing its utilization in diverse metabolic pathways. In bacteria, such as Escherichia coli and Streptococcus pneumoniae, structural and kinetic studies have demonstrated that FucU proteins assemble into complex oligomeric structures (e.g., decameric toroids) and accelerate the conversion of fucose released by glycoside hydrolases into the preferred α-form required by downstream isomerases, thus efficiently linking fucose hydrolysis with its catabolism (see."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": " In contrast, studies in mammalian systems have shown that despite a high degree of sequence conservation, the quaternary structural alterations of FucU homologues result in markedly reduced catalytic activity; yet, when overexpressed these proteins enhance the incorporation of L‐fucose into glycoproteins via the salvage pathway, emphasizing a regulatory role in glycosylation (see."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": " Moreover, structural and NMR analyses—including comparisons with paralogous proteins such as RbsD—suggest that in some species FucU may function primarily as a cytoplasmic sugar‐binding protein, with the capacity to bind L‐fucose without necessarily catalyzing its anomeric conversion (see."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Additional findings indicate that altered expression levels of fucose mutarotases can influence cellular responses to antimicrobial agents, underscoring the potential pleiotropic roles of these proteins (see."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": " Collectively, these studies reveal that FucU homologues play multifaceted roles in fucose metabolism across prokaryotes and eukaryotes, acting not only as catalysts for anomeric interconversion but also as regulators of sugar flux into biosynthetic pathways.\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n (1,2,3,4,5,6,7,8,9)\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Kwang-Hoon Lee, Kyoung-Seok Ryu, Min-Sung Kim, et al. 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