02592nas a2200277 4500008004100000022001400041245008800055210006900143260007300212300001200285490000900297520161200306653001701918653003801935653002201973653002101995653002102016653002002037100002502057700002002082700002602102700002402128700002102152700002502173856011602198 2013 eng d a1570-963900aPolyproline fold-In imparting kinetic stability to an alkaline serine endopeptidase0 aPolyproline foldIn imparting kinetic stability to an alkaline se aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a708-7160 v18343 a

Polyproline II (PPII) fold, an unusual structural element was detected in the serine protease from Nocardiopsis sp. NCIM 5124 (NprotI) based on far UV circular dichroism spectrum, structural transitions of the enzyme in presence of GdnHCl and a distinct isodichroic point in chemical and thermal denaturation. The functional activity and conformational transitions of the enzyme were studied under various denaturing conditions. Enzymatic activity of NprotI was stable in the vicinity of GdnHCl upto 6.0 M concentration, organic solvents viz, methanol, ethanol, propanol (all 90% v/v), acetonitrile (75% v/v) and proteases such as trypsin, chymottypsin and proteinase K (NprotI:protease 10:1). NprotI seems to be a kinetically stable protease with a high energy barrier between folded and unfolded states. Also, an enhancement in the activity of the enzyme was observed in 1 M GdnHCl upto 8 h, in organic solvents (75% v/v) for 72 h and in presence of proteolytic enzymes. The polyproline fold remained unaltered or became more prominent under the above mentioned conditions. However, it diminished gradually during thermal denaturation above 60 degrees C. Thermal transition studies by differential scanning calorimetry (DSC) showed scan rate dependence as well as irreversibility of denaturation, the properties characteristic of kinetically stable proteins. This is the first report of PPII helix being the global conformation of a non structural protein, an alkaline serine protease, from a microbial source, imparting kinetic stability to the protein. (C) 2013 Elsevier B.V. All rights reserved.

10aConformation10adifferential scanning calorimetry10aKinetic stability10aNocardiopsis sp.10aPolyproline fold10aSerine protease1 aRohamare, Sonali, B.1 aDixit, Vaishali1 aNareddy, Pavan, Kumar1 aSivaramakrishna, D.1 aSwamy, Musti, J.1 aGaikwad, Sushama, M. uhttps://library.ncl.res.in/content/polyproline-fold-imparting-kinetic-stability-alkaline-serine-endopeptidase-002079nas a2200229 4500008004100000022001400041245008700055210006900142260007300211300001000284490000700294520124300301653004001544653001701584653001901601653002001620653001401640100002701654700002701681700002501708856011601733 2014 eng d a0141-813000aConformational transitions of cinnamoyl CoA reductase 1 from leucaena leucocephala0 aConformational transitions of cinnamoyl CoA reductase 1 from leu aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a30-350 v643 a

Conformational transitions of cinnamoyl CoA reductase, a key regulatory enzyme in lignin biosynthesis, from Leucaena leucocephala (L1-CCRH1) were studied using fluorescence and circular dichroism spectroscopy. The native protein possesses four trp residues exposed on the surface and 66% of helical structure, undergoes rapid structural transitions at and above 45 C and starts forming aggregates at 55 C. LI-CCRH1 was transformed into acid induced (pH 2.0) molten globule like structure, exhibiting altered secondary structure, diminished tertiary structure and exposed hydrophobic residues. The molten globule like structure was examined for the thermal and chemical stability. The altered secondary structure of Ll -CCRH1 at pH 2.0 was stable up to 90 C. Also, in presence of 0.25 M guanidine hydrochloride (GdnHCI), it got transformed into different structure which was stable in the vicinity of 2 M GdnHCI (as compared to drastic loss of native structure in 2 M GdnHC1) as seen in far UV-CD spectra. The structural transition of LI-CCRH1 at pH 2.0 followed another transition after readjusting the pH to 8.0, forming a structure with hardly any similarity to that of native protein. (C) 2013 Elsevier B.V. All rights reserved.

10aAggregation Cinnamoyl CoA reductase10aConformation10aMolten globule10aThermostability10aUnfolding1 aSonawane, Prashant, D.1 aKhan, Bashir, Mohammad1 aGaikwad, Sushama, M. uhttps://library.ncl.res.in/content/conformational-transitions-cinnamoyl-coa-reductase-1-leucaena-leucocephala-002220nas a2200241 4500008004100000022001400041245012000055210006900175260000900244300001200253490000800265520138800273653001701661653001901678653001101697653001901708653002301727653002401750100002801774700002101802700002501823856013001848 2019 eng d a0003-986100aInvestigation of structural and saccharide binding transitions of Bauhinia purpurea and Wisteria floribunda lectins0 aInvestigation of structural and saccharide binding transitions o cFEB  a134-1420 v6623 a

Two novel medicinally important legume lectins from Bauhinia purpurea (BPL) and Wisteria floribunda (WFL) possessing extended sugar binding site were investigated for functional and conformational transitions using biochemical and biophysical techniques as well as bioinformatical tools. Homology model of BPL was constructed using the Schrodinger suite and docked with N-acetyl galactosamine and T-antigen disaccharide (Gal beta 1-3GalNAc alpha O-Me). The longer loop D in the structure of WFL compared to that in BPL was found to be responsible for its specificity to LacdiNac (beta-D-GalNAc-[1 -> 4]-DGlcNAc) over Gal beta 1-3GalNAc. BPL remained functionally stable up to 40 degrees C whereas WFL remained stable upto 70 degrees C indicating the strength of the sugar binding site geometry. Both the lectins showed intense but non-specific secondary structure in the range of 65-90 degrees C. WFL showed rapid aggregation above 80 degrees C as indicated by light scattering intensity. The lectins showed simultaneous dissociation and multistate unfolding in the vicinity of GdnHCl. At pH 1.0, both the lectins exhibited molten globule like structures, which were characterized further and were found to respond in a different way towards denaturants. The results have provided valuable insights into the molecular basis of the activity and stability of the two lectins.

10aConformation10aHomology model10aLectin10aMolten globule10asaccharide binding10aThermal aggregation1 aAgrawal, Sanskruthi, B.1 aGhosh, Deepanjan1 aGaikwad, Sushama, M. uhttps://library.ncl.res.in/content/investigation-structural-and-saccharide-binding-transitions-bauhinia-purpurea-and-wisteria