Conformational Changes in the Reaction of Pyridoxal Kinase

Ming Hui Li, Francis Kwok, Wen Rui Chang, Sheng Quan Liu, Chun Lap Samuel Lo, Ji Ping Zhang, Tao Jiang, Dong Cai Liang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

32 Citations (Scopus)

Abstract

To understand the processes involved in the catalytic mechanism of pyridoxal kinase (PLK), we determined the crystal structures of PLK-AMP-PCP-pyridoxamine, PLK-ADP-PLP, and PLK-ADP complexes. Comparisons of these structures have revealed that PLK exhibits different conformations during its catalytic process. After the binding of AMP-PCP (an analogue that replaced ATP) and pyridoxamine to PLK, this enzyme retains a conformation similar to that of the PLK-ATP complex. The distance between the reacting groups of the two substrates is 5.8 Å apart, indicating that the position of ATP is not favorable to spontaneous transfer of its phosphate group. However, the structure of PLK-ADP-PLP complex exhibited significant changes in both the conformation of the enzyme and the location of the ligands at the active site. Therefore, it appears that after binding of both substrates, the enzyme-substrate complex requires changes in the protein structure to enable the transfer of the phosphate group from ATP to vitamin B6. Furthermore, a conformation of the enzyme-substrate complex before the transition state of the enzymatic reaction was also hypothesized.
Original languageEnglish
Pages (from-to)17459-17465
Number of pages7
JournalJournal of Biological Chemistry
Volume279
Issue number17
DOIs
Publication statusPublished - 23 Apr 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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