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The crystal structure of seabream antiquitin reveals the structural basis of its substrate specificity
Author(s) -
Tang Wai-Kwan,
Wong Kam-Bo,
Lam Yuk-Man,
Cha Sun-Shin,
Cheng Christopher H.K.,
Fong Wing-Ping
Publication year - 2008
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 - 10.1016/j.febslet.2008.07.059
Subject(s) - substrate (aquarium) , cofactor , chemistry , active site , stereochemistry , carboxylate , nad+ kinase , binding site , crystal structure , crystallography , biochemistry , enzyme , biology , ecology
The crystal structure of seabream antiquitin in complex with the cofactor NAD + was solved at 2.8 Å resolution. The mouth of the substrate‐binding pocket is guarded by two conserved residues, Glu120 and Arg300. To test the role of these two residues, we have prepared the two mutants E120A and R300A. Our model and kinetics data suggest that antiquitin's specificity towards the substrate α‐aminoadipic semialdehyde is contributed mainly by Glu120 which interacts with the α‐amino group of the substrate. On the other hand, Arg300 does not have any specific interaction with the α‐carboxylate group of the substrate, but is important in maintaining the active site conformation.