01925nas a2200205   4500008004100000022001400041245007200055210006900127260007300196300001200269490000800281520119200289653001701481653002301498653002401521653002501545100002401570700002501594856010001619       2009                        eng d  a0304-389400aStudies on biological reduction of chromate by Streptomyces griseus0 aStudies on biological reduction of chromate by Streptomyces gris  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a539-5450 v1693 a<p>Chromium is a toxic heavy metal used in various industries and leads to environmental pollution due to improper handling. The most toxic form of chromium Cr(VI) can be converted to less toxic Cr(III) by reduction. Among the actinomycetes tested for chromate reduction, thirteen strains reduced Cr(VI) to Cr(III), of which one strain of Streptomyces griseus (NCIM 2020) was most efficient showing complete reduction within 24h. The organism was able to use a number of carbon sources as electron donors. Sulphate, nitrate, chloride and carbonate had no effect on chromate reduction during growth while cations such as Cd, Ni, Co and Cu were inhibitory to varying degrees. Chromate reduction was associated with the bacterial cells and sonication was the best method of cell breakage to release the enzyme. The enzyme was constitutive and did not require presence of chromate during growth for expression of activity. Chromate reduction with cell free extract (CFE) was observed without added NADH. However, addition of NAD(P)H resulted in 2-3-fold increase in activity. Chromate reductase showed optimum activity at 28 degrees C and pH 7 (C) 2009 Elsevier B.V. All rights reserved.</p>10aBioreduction10aChromate reductase10aHexavalent chromium10aStreptomyces griseus1 aPoopal, Ashwini, C.1 aLaxman, Ryali, Seeta  uhttps://library.ncl.res.in/content/studies-biological-reduction-chromate-streptomyces-griseus-002593nas a2200277   4500008004100000022001400041245009900055210006900154260005700223300001200280490000700292520162200299653001401921653002601935653003101961653002001992653001402012653002502026653002802051100002102079700002102100700001802121700002502139700002502164856012602189       2014                        eng d  a0175-757100aSubtilase from Beauveria sp.: conformational and functional investigation of unusual stability0 aSubtilase from Beauveria sp conformational and functional invest  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcSEP  a393-4030 v433 a<p>Retention of total activity of the subtilisin-like serine protease from Beauveria sp. MTCC 5184 (Bprot) in the vicinity of (1) 3 M GdnHCl for 12 h, (2) 50 % methanol and dimethyl sulfoxide each for 24 h, and (3) proteolytic enzymes (trypsin, chymotrypsin, and proteinase K) for 48 h led to expect the enzyme to be a kinetically stable protein. Also, the structure of the protein was stable at pH 2.0. Biophysical characterization and conformational transitions were monitored using steady-state and time-resolved fluorescence, FTIR, and CD spectroscopy. Single tryptophan in the protein exists as two conformers, in hydrophobic and polar environment. The secondary structure of Bprot was stable in 3 M GdnHCl as seen in far-UV CD spectra. The active fraction of Bprot obtained from size-exclusion chromatography in the presence of GdnHCl (1.0-3.0 M) eluted at reduced retention time. The peak area of inactive or denatured protein with the same retention time as that of native protein increased with increasing concentration of denaturant (1.0-4.0 M GdnHCl). However, the kinetics of GdnHCl-induced unfolding as studied from intrinsic fluorescence revealed k (unf) of native protein to be 5.407 x 10(-5) s(-1) and a half-life of 3.56 h. The enzyme is thermodynamically stable in spite of being resistant to the denaturant, which could be due to the effect of GdnHCl imparting rigidity to the active fraction and simultaneously unfolding the partially unfolded protein that exists in equilibrium with the folded active protein. Thermal and pH denaturation of Bprot exhibited interesting structural transitions.</p>10aBeauveria10aChemical denaturation10aConformational transitions10aSerine protease10aSubtilase10aThermal denaturation10aThermodynamic stability1 aDalal, Sayli, A.1 aMore, Snehal, V.1 aShankar, Shiv1 aLaxman, Ryali, Seeta1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/subtilase-beauveria-sp-conformational-and-functional-investigation-unusual-stability-0