Search Results - (Author, Cooperation:K. Rajashankar)
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1R. P. Hayes ; Y. Xiao ; F. Ding ; P. B. van Erp ; K. Rajashankar ; S. Bailey ; B. Wiedenheft ; A. Ke
Nature Publishing Group (NPG)
Published 2016Staff ViewPublication Date: 2016-02-11Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsPublished by: -
2Rana, M. S., Kumar, P., Lee, C.-J., Verardi, R., Rajashankar, K. R., Banerjee, A.
American Association for the Advancement of Science (AAAS)
Published 2018Staff ViewPublication Date: 2018-01-12Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyGeosciencesComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Biochemistry, Cell BiologyPublished by: -
3Mieher, J. L., Larson, M. R., Schormann, N., Purushotham, S., Wu, R., Rajashankar, K. R., Wu, H., Deivanayagam, C.
The American Society for Microbiology (ASM)
Published 2018Staff ViewPublication Date: 2018-06-22Publisher: The American Society for Microbiology (ASM)Print ISSN: 0019-9567Electronic ISSN: 1098-5522Topics: MedicinePublished by: -
4Barton, William A. ; Lesniak, Jacob ; Biggins, John B. ; Jeffrey, Philip D. ; Jiang, Jiqing ; Rajashankar, K. R. ; Thorson, Jon S. ; Nikolov, Dimitar B.
[s.l.] : Nature Publishing Group
Published 2001Staff ViewISSN: 1072-8368Source: Nature Archives 1869 - 2009Topics: BiologyMedicineNotes: [Auszug] Metabolite glycosylation is affected by three classes of enzymes: nucleotidylyltransferases, which activate sugars as nucleotide diphospho-derivatives, intermediate sugar-modifying enzymes and glycosyltransferases, which transfer the final derivatized activated sugars to aglycon substrates. One of ...Type of Medium: Electronic ResourceURL: -
5Staff View
ISSN: 1420-9071Keywords: Key words. Phospholipase A2; molecular evolution;inhibitor; pharmacological sites; enzyme activity; enzyme toxicity.Source: Springer Online Journal Archives 1860-2000Topics: BiologyMedicineNotes: Abstract. Snake venom oligomeric neurotoxins offer several unique examples of modulation of phospholipase A2 (PLA2) activity generated by molecular evolution. This phenomenon was found in evolutionary younger snakes and is probably common for representatives of the genus Vipera. At present, the best-studied example is the heterodimeric neurotoxin vipoxin from the venom of the southeast European snake Vipera ammodytes meridionalis. It is a complex between a basic strongly toxic PLA2 and an acidic and catalytically inactive PLA2-like component (Inh). This is the first reported example of a high degree of structural homology (62%) between an enzyme and its natural protein inhibitor. The inhibitor is a product of the divergent evolution of the unstable PLA2 in order to stabilize it and to preserve the pharmacological activity/toxicity for a long time. Inh reduces both the catalytic activity and toxicity of PLA2. Vipoxin also illustrates evolution of the catalytic into a inhibitory function. Vipoxin analogues have been found in the venom of viperid snakes inhabiting diverse regions of the world. An attempt is made to explain modulation of the toxic function by the three-dimensional structure of vipoxin.Type of Medium: Electronic ResourceURL: -
6Rajashankar, K. R. ; Ramakumar, S. ; Jain, R. M. ; Chauhan, V. S.
New York : Wiley-Blackwell
Published 1997Staff ViewISSN: 0006-3525Keywords: x-ray diffraction ; crystal structure ; dehydrophenylalanine ; constrained peptides ; 310-helix ; Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyNotes: An Nα-protected model pentapeptide containing two consecutive ΔPhe residues, Boc-Leu-ΔPhe-ΔPhe-Ala-Phe-NHMe, has been synthesized by solution methods and fully characterized. 1H-nmr studies provided evidence for the occurrence of a significant population of a conformer having three consecutive, intramolecularly H-bonded β-bends in solution. The solid state structure has been determined by x-ray diffraction methods. The crystals grown from aqueous methanol are orthorhombic, space group P212121, a = 11.503(2), b = 16.554(2), c = 22.107(3) Å, V = 4209(1) Å,3 and Z = 4. The x-ray data were collected on a CAD4 diffractometer using CuKa radiation (λ = 1.5418 Å). The structure was determined using direct methods and refined by full-matrix least-squares procedure. The R factor is 5.3%. The molecule is characterized by a right handed 310-helical conformation (〈φ〉 = -68.2°, 〈ψ〉 = -26.3°), which is made up of two consecutive type III β-bends and one type I β-bend. In the solid state the helical molecules are aligned head-to-tail, thus forming long rod like structures. A comparison with other peptide structures containing consecutive ΔPhe residues is also provided. The present study confirms that the -ΔPhe-ΔPhe-sequence can be accommodated in helical structures. © 1997 John Wiley & Sons, Inc. Biopoly 42: 373-382, 1997Additional Material: 4 Ill.Type of Medium: Electronic Resource -
7Rajashankar, K. R. ; Ramakumar, S. ; Mal, T. K. ; Jain, R. M. ; Chauhan, V. S.
New York : Wiley-Blackwell
Published 1995Staff ViewISSN: 0006-3525Keywords: Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyNotes: α,β-Dehydro amino acid residues are known to constrain the peptide backbone to the β-bend conformation. A pentapeptide containing only one α,β dehydrophenylalanine (ΔPhe) residue has been synthesized and crystallized, and its solid state conformation has been determined. The pentapeptide Boc-Leu-Phe-Ala-ΔPhe-Leu-OMe (C39H55N5O8, Mw = 721.9) was crystallized from aqueous methanol. Monoclinic space group was P21, a = 10.290(2)°, b = 17.149(2)°, c = 12.179(2) Å, β = 96.64(1)° with two molecules in the unit cell. The x-ray (Mo Kα, λ = 0.7107A) intensity data were collected using a CAD4 diffractometer. The crystal structure was determined by direct methods and refined using least-squares technique. R = 4.4% and Rw = 5.4% for 4403 reflections having |F0| ≥ 3σ(|F0|). All the peptide links are trans and the pentapeptide molecule assumes 310-helical conformation. The mean φ,ψ values, averaged over the first four residues, are -64.4°, -22.4° respectively. There are three 4 → 1 intramolecular hydrogen bonds, characteristic of 310,-helix. In the crystal, the peptide helices interact through two head-to-tail. N—H—O intermolecular hydrogen bonds. The peptide molecules related by 21, screw symmetry form a skewed assembly of helices. © 1995 John Wiley & Sons, Inc.Additional Material: 2 Ill.Type of Medium: Electronic ResourceURL: