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UV resonance Raman spectroscopic studies on the behavior of Tyr8 in human hematopoietic prostaglandin D 2 synthase
Author(s) -
Uchida Yoshiko,
Aritake Kosuke,
Urade Yoshihiro,
Kohzuma Takamitsu
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a273
Subject(s) - chemistry , raman spectroscopy , deprotonation , resonance raman spectroscopy , glutathione , enzyme , stereochemistry , biochemistry , ion , physics , optics , organic chemistry
Human hematopoietic prostaglandin D 2 synthase (H‐PGDS) is known to be activated by various divalent metal ions. H‐PGDS catalyzes the isomerization of prostaglandin (PG) H 2 to PGD 2 , which is known to be an allergy mediator. The enzyme requires glutathione (GSH) as a cofactor for expression of the enzymatic activity. The metal ion assisted activation mechanism of H‐PGDS was investigated by UV resonance Raman (RR) spectroscopy (excitation at 244 nm). UVRR spectra of H‐PGDS in the presence of Mg 2+ showed a lower frequency shift of Y8a Raman band from 1618 cm −1 to 1599 cm −1 , which is characteristic to tyrosine phenolate. The deprotonated tyrosine residue was identified to be Tyr8 by site‐directed mutagenesis studies. The Y8a Raman band (1599 cm −1 ) of Mg 2+ H‐PGDS complex was shifted to 1611 cm −1 in the presence of GSH. The 12 cm −1 higher frequency shift strongly suggests re‐protonation of Tyr8 residue. The lower frequency of the Raman band (1611 cm −1 ) would be implicated the formation of a H‐bonding between Tyr8 phenol and thiolate group of GSH. Development of Basic Technologies for Advanced Production Methods Using Microorganism Functions (by NEDO)