Characterization of novel acetyltransferases found in budding and fission yeasts that detoxify a proline analogue, azetidine-2-carboxylic acid.
We recently found that budding yeast Saccharomyces cerevisiae sigma1278b, but not genome project strain S288C, has a gene conferring resistance to L-azetidine-2-carboxylic acid (AZC), a toxic four-membered ring analogue of L-proline. Also, the gene, designated as MPR1, encodes a novel acetyltransferase that detoxifies AZC via acetylation. We now report the results of subsequent work. On a homology search with MPR1, we detected a gene in fission yeast Schizosaccharomyces pombe. This gene, designated as ppr1(+) (pombe MPR1), is responsible for the AZC-resistance of S. pombe as judged from the results of gene disruption and overexpression experiments. Escherichia coli cells expressing ppr1(+), like ones expressing MPR1, were resistant to AZC and produced an AZC acetyltransferase. We further found that the enzymes encoded by MPR1 and ppr1(+) were homodimers, and catalyzed the acetylation of AZC but not any other L-proline-related compounds. Ppr1p was more thermostable than Mpr1p, although Ppr1p had a lower optimum temperature than Mpr1p. The higher AZC acetylation activity of Mpr1p, in comparison to that of Ppr1p, was attributed to the larger k(cat)/K(m) value for acetyl-CoA of Mpr1p than that of Ppr1p.
Nomura
Michiyo
M
Department of Bioscience, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka-cho, Fukui 910-1195.
Nakamori
Shigeru
S
Takagi
Hiroshi
H
D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001383:Azetidinecarboxylic Acid / Q000737:chemistry / Q000633:toxicity*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics; D025141:Drug Resistance, Fungal; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012568:Schizosaccharomyces / Q000187:drug effects / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D018797:Cell Cycle Proteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; D001383:Azetidinecarboxylic Acid; D000123:Acetyltransferases; D011494:Protein Kinases; C413334:Mpr1 protein, S pombe