Global expression analysis of the yeast Lachancea (Saccharomyces) kluyveri reveals new URC genes involved in pyrimidine catabolism.

Pyrimidines are important nucleic acid precursors which are constantly synthesized, degraded, and rebuilt in the cell. Four degradation pathways, two of which are found in eukaryotes, have been described. One of them, the URC pathway, has been initially discovered in our laboratory in the yeast Lachancea kluyveri.

Crystal structure of D-serine dehydratase from Escherichia coli.

D-Serine dehydratase from Escherichia coli is a member of the β-family (fold-type II) of the pyridoxal 5'-phosphate-dependent enzymes, catalyzing the conversion of D-serine to pyruvate and ammonia. The crystal structure of monomeric D-serine dehydratase has been solved to 1.97Å-resolution for an orthorhombic data set by molecular replacement.

A new expression vector for production of enzymes in the yeast Saccharomyces (Lachancea) kluyveri.

We overexpressed and purified enzymes involved in the pyrimidine catabolic pathway in the yeast Saccharomyces (Lachancea) kluyveri. A new vector was therefore designed, providing the first specific expression system in Saccharomyces kluyveri. The URC1 gene was overexpressed and a soluble protein obtained and successfully purified using the C-terminally added His-tag.

(31)P NMR spectroscopy senses the microenvironment of the 5'-phosphate group of enzyme-bound pyridoxal 5'-phosphate.

In this review it is demonstrated that (31)P NMR spectroscopy can be used to elucidate information about the microenvironment around the phosphate group of enzyme-bound pyridoxal 5'-phosphate (PLP). The following information can be obtained for all PLP-dependent enzymes: 1) the protonation state of the 5'-phosphate and its exposure to solvent, and 2) tightness of binding of the 5'-phosphate. In addition, the 5-phosphate can report on the protonation state of the Schiff base lysine in some enzymes.

(31)P NMR studies of O-acetylserine sulfhydrylase-B from Salmonella typhimurium.

O-Acetylserine sulfhydrylase (OASS) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the conversion of O-acetylserine and bisulfide to l-cysteine and acetate in bacteria and higher plants. Enteric bacteria have two isozymes of OASS, A and B, produced under aerobic and anaerobic growth conditions, respectively, with different substrate specificities. The (31)P chemical shift of the internal and external Schiff bases of PLP in OASS-B are further downfield compared to OASS-A, suggesting a tighter binding of the cofactor in the B-isozyme.