Moonlighting protein in Starkeyomyces koorchalomoides: characterization of dihydrolipoamide dehydrogenase as a protein acetyltransferase utilizing acetoxycoumarin as the acetyl group donor.

In this report we have identified for the first time a transacetylase (TAase) in a mesophilic fungi Starkeyomyces koorchalomoides catalyzing the transfer of acetyl group from polyphenolic acetate (PA) to a receptor protein glutathione S-transferase (GST). An elegant assay procedure was established for TAase based on its ability to mediate inhibition of GST by 7,8-diacetoxy-4-methylcoumarin (DAMC), a model PA. Utilizing this assay procedure, S. koorchalomoides TAase was purified to homogeneity. TAase was found to have MW of 50 kDa. The purified enzyme exhibited maximum activity at 45 degrees C at pH 6.8. The N-terminal sequence of purified fungal TAase (ANDASTVED) showed identity with corresponding N-terminal sequence of dihydrolipoamide dehydrogenase (LADH), a mitochondrial matrix enzyme and an E3 component of pyruvate dehydrogenase complex (PDHC). TAase was found to have all the properties of LADH and avidly interacted with the anti-LADH antibody. TAase catalyzed acetylation of GST by DAMC was identified by LC-MS/MS and a single lysine residue (Lys-113) was found to be acetylated. Further, recombinant LADH from Streptococcus pneumoniae lacking lipoyl domain was found to exhibit little TAase activity, suggesting the role of lipoyl domain in the TAase activity of LADH. These observations bear evidence for the protein acetyltransferase activity of LADH. Such an activity of LADH can be attributed as a moonlighting function of the enzyme.

Chemical variability in the essential oil components of Achillea millefolium agg. from different Himalayan habitats (India).

Essential oil diversity was studied in wild Achillea millefolium from two different high altitude Himalayan habitats (1600 m, 2850 m) and their cultivated populations under uniform environmental conditions at lower altitudes of Jammu (300 m). The populations proved to represent two different ecotypes: the 1,8-cineole type and the borneol type with appreciable differences in the contents of oils and mono- and sesquiterpenes. Populations from all these habitats showed considerable overlap in various constituents and the major components were characterized as beta-pinene (10.6 % - 17.7 %), 1,8-cineole (3.0 % - 15.1 %), borneol (0.2 % - 12.1 %), and beta-caryophyllene (8.5 % - 16.2 %). No variation in morphology and chromosome number was observed under comparable environmental conditions from different habitats. Preliminary investigation indicates the existence of different ecotypes from the Himalayan habitats.

Essential oil composition of aerial parts of Angelica glauca growing wild in North-West Himalaya (India).

Fresh aerial parts of Angelica glauca, growing wild in Kashmir valley in higher Himalaya (Jammu and Kashmir, India), collected at flowering stage from different locations, on hydro-distillation provided a refreshing light pale coloured essential oil with characteristic floral woody flavour. The oil was found to be a complex mixture of mono- and sesquiterpenes and 34 compounds accounting for nearly 97.4% of the oil were characterized with the help of capillary GC, GC-MS, and NMR. Major compounds of the oil were characterized as alpha-phellandrene (13.5%), trans-carveol (12.0%), beta-pinene (11.7%), thujene (7.5%), beta-caryophyllene oxide (7.2%), beta-caryophyllene (7.0%), gamma-terpinene (6.7%), nerolidol (6.5%), beta-bisabolene (5.2%) and germacrene D (4.5%). It is the first report to exploit the essential oil from Himalayan A. glauca herb collected at flowering stage.