Biomedical subjects

N Peitzsch

Publications and source records attributed to N Peitzsch.

3 recordsLinked to original sources

PubMed1999

Isolation and characterization of a calendic acid producing (8,11)-linoleoyl desaturase.

For the biosynthesis of calendic acid a (8,11)-linoleoyl desaturase activity has been proposed. To isolate this desaturase, PCR-based cloning was used. The open reading frame of the isolated full-length cDNA is a 1131 bp sequence encoding a protein of 377 amino acids. For functional identification the cDNA was expressed in Saccharomyces cerevisiae, and formation of calendic acid was analyzed by RP-HPLC. The expression of the heterologous enzyme resulted in a significant amount of calendic acid presumably esterified within phospholipids. The results presented here identify a gene encoding a new type of (1,4)-acyl lipid desaturase.

Amino Acid Sequence↗

PubMed1998

Alcaligenes eutrophus as a bacterial chromate sensor.

In Alcaligenes eutrophus CH34, determinants encoding inducible resistance to chromate (chr) and to cobalt and nickel (cnr) are located adjacent to each other on plasmid pMOL28. To develop metal-sensing bacterial strains, a cloned part of plasmid pMOL28, which contains both determinants, was mutated with Tn5-lacZ. The chr::lacZ fusions were specifically induced by chromium; cnr was induced best by Ni2+ but was also induced by Co2+, Mn2+, chromate, Cu2+, Cd2+, and Zn2+. The broad-host-range IncP1 plasmid pEBZ141, which contains a chr::lux fusion, was constructed. A. eutrophus AE104(pEBZ141), carrying a chr::lux transcriptional fusion, could be used as a biosensor for chromate when cultivated in glycerol as an optimal carbon source. Chromate and bichromate were the best inducers; induction by Cr3+ was 10 times lower, and other ions induced only a little or not at all. Interactions among induction of the chr resistance determinant, chromate reduction, chromate accumulation, and the sulfate concentration of the growth medium were demonstrated.

Alcaligenes↗

PubMed1998

CHR, a novel family of prokaryotic proton motive force-driven transporters probably containing chromate/sulfate antiporters.

We describe a small family of proteins, CHR, which contains members that function in chromate and/or sulfate transport. CHR proteins occur in bacteria and archaea. They consist of about 400 amino acyl residues, appear to have 10 transmembrane alpha-helical segments in an unusual 4+6 arrangement, and arose by an intragenic duplication event.

Amino Acid Sequence↗