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Substitution of one calcium‐binding amino acid strengthens substrate binding in a thermophilic alginate lyase
Author(s) -
Wang Bing,
Ji ShiQi,
Ma XiaoQing,
Lu Ming,
Wang LuShan,
Li FuLi
Publication year - 2018
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12965
Subject(s) - glycosidic bond , binding site , chemistry , substrate (aquarium) , ligand (biochemistry) , stereochemistry , biochemistry , lyase , amino acid , enzyme , biology , receptor , ecology
Ligand binding is sensitive to temperatures since noncovalent bonds between the binding site and ligand could be broken by heat. How metal ion‐binding amino acids in alginate lyase evolve to achieve tight substrate binding in a hostile environment remains unknown. An endolytic alginate lyase AlgAT0 specifically cleaved the M–G glycosidic bond and released disaccharides as the main end product. Four conserved calcium‐binding sites were predicted and the supplement of Ca 2+ led to enhanced substrate binding and protein stability. Among the four conserved calcium‐binding sites, one substitution of aspartate for glutamate in AlgAT0 was proved to stimulate Ca 2+ affinity. This study suggested that substrate affinity of polysaccharide lyases could be improved by tight binding to Ca 2+ via one amino acid substitution.