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Identification of a pyridoxine (pyridoxamine) 5′‐phosphate oxidase from Arabidopsis thaliana
Author(s) -
Sang Yuying,
Barbosa Jose M.,
Wu Hongzhuan,
Locy Robert D.,
Singh Narendra K.
Publication year - 2007
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.2006.12.028
Subject(s) - pyridoxamine , biochemistry , transit peptide , complementary dna , chemistry , pyridoxal , microbiology and biotechnology , biology , enzyme , gene , chloroplast , plastid
Pyridoxine (pyridoxamine) 5′‐phosphate oxidase (PPOX) catalyzes the oxidative conversion of pyridoxamine 5′‐phosphate (PMP) or pyridoxine 5′‐phosphate (PNP) to pyridoxal 5′‐phosphate (PLP). The At5g49970 gene of Arabidopsis thaliana shows homology to PPOX's from a number of organisms including the Saccharomyces cerevisiae PDX3 gene. A cDNA corresponding to putative A. thaliana PPOX ( At PPOX) was obtained using reverse transcriptase‐polymerase chain reaction and primers landing at the start and stop codons of At5g49970 . The putative At PPOX is 530 amino acid long and predicted to contain three distinct parts: a 64 amino acid long N‐terminal putative chloroplast transit peptide, followed by a long Yjef_N domain of unknown function and a C‐terminal Pyridox_oxidase domain. Recombinant proteins representing the C‐terminal domain of At PPOX and At PPOX without transit peptide were expressed in E. coli and showed PPOX enzyme activity. The PDX3 knockout yeast deficient in PPOX activity exhibited sensitivity to oxidative stress. Constructs of AtPPOX cDNA of different lengths complemented the PDX3 knockout yeast for oxidative stress. The role of the Yjef_N domain of At PPOX was not determined, but it shows homology with a number of conserved hypothetical proteins of unknown function.