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Different phosphate binding modes of Streptomyces griseus aminopeptidase between crystal and solution states and the status of zinc‐bound water
Author(s) -
Harris Michael N,
Ming Li-June
Publication year - 1999
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/s0014-5793(99)00879-0
Subject(s) - phosphate , chemistry , streptomyces griseus , zinc , fluoride , aminopeptidase , binding site , inorganic chemistry , ion , crystal (programming language) , streptomyces , non competitive inhibition , crystallography , enzyme , nuclear chemistry , stereochemistry , biochemistry , amino acid , biology , organic chemistry , bacteria , leucine , computer science , genetics , programming language
Phosphate shows a non‐competitive inhibition toward a Streptomyces aminopeptidase (sAP) between pH 5.85 ( K i =0.48 mM) and 9.0 (110 mM), with a p K a of 7.1 likely due to ionization of H 2 PO 4 − . This non‐competitive inhibition pattern indicates that phosphate binding to sAP in solution is different from that in the crystal structure, where phosphate is bound to the active site Zn(II) ions. Fluoride uncompetitively inhibits sAP from pH 5.5 ( K i =3.72 mM) to 9.0 (43.6 mM), with a p K a of ∼6.2 likely due to a coordinated water. The different inhibition natures and p K a values indicate that the two inhibitors bind at different locations.