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Crystal structure of two quaternary complexes of dethiobiotin synthetase, enzyme‐MgADP‐AlF 3 ‐diaminopelargonic acid and enzyme‐MgADP‐dethiobiotin‐phosphate; implications for catalysis
Author(s) -
Käck Helena,
Sandmark Jenny,
Schneider Gunter,
Lindqvist Ylva,
Gibson Katharine J.
Publication year - 1998
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560071209
Subject(s) - chemistry , enzyme , stereochemistry , substrate (aquarium) , catalysis , reaction intermediate , enzyme catalysis , active site , crystallography , biochemistry , biology , ecology
Abstract The crystal structures of two complexes of dethiobiotin synthetase, enzyme‐diaminopelargonic acid‐MgADP‐AlF 3 and enzyme‐dethiobiotin‐MgADP‐Pi, respectively, have been determined to 1.8 Å resolution. In dethiobiotin synthetase, AlF 3 together with carbamylated diaminopelargonic acid mimics the phosphorylated reaction intermediate rather than the transition state complex for phosphoryl transfer. Observed differences in the binding of substrate, diaminopelargonic acid, and the product, dethiobiotin, suggest considerable displacements of substrate atoms during the ring closure step of the catalytic reaction. In both complexes, two metal ions are observed at the active site, providing evidence for a two‐metal mechanism for this enzyme.