Cystine peptides.

Abstract

NHCH3 (X = Gly 1, Ala 2, Aib 3, Leu 4 and D‐Ala 5), have been investigated by Raman and circular dichroism (CD) spectroscopy. Solid state Raman spectra are consistent with β‐turn conformations in all five peptides. These peptides exhibit similar conformations of the disulfide segment in the solid state with a characteristic disulfide stretching frequency at 519 ± 3 cm‐1, indicative of a trans‐gauche‐gauche arrangement about the Cα—Cβ—S—S—Cβ—Cα bonds. The results correlate well with the solid state conformations determined by X‐ray diffraction for peptides 3 and 4. CD studies in chloroform and dimethylsulfoxide establish solvent dependent conformational changes for peptides 1, 3 and 5. Disulfide chirality has been derived using the quadrant rule. CD results together with previously reported nuclear magnetic resonance (n.m.r.) data suggest a conformational coupling between the peptide backbone and the disulfide segment.

Characterization of (Boc‐Cys/Sec‐NHMe)2 and (Boc‐Cys/Sec‐OMe)2: Evidence of local conformational difference between disulfide and diselenide

“…Conformational analysis of cystine and selenocystine derivatives using NMR spectroscopy and DFT has revealed similar structural features for the corresponding derivatives with antiparallel orientation of Cys/Sec residues about the disulfide/diselenide bridges. The absence of aromatic residues in designed compounds have permitted unambiguous assignment of the handedness of disulfide/diselenide based on the sign of Cotton effect (CE) in the far‐ultraviolet (UV) region of the CD spectra . Similarly, the far‐UV CD spectra of the cystine derivatives of the present study were found to exhibit negative bands and those of the selenocystine derivatives positive bands confirming the difference in conformational preference of disulfides and diselenides in solution.…”

Comparison of Privacy Preserving Single-Keyword Search and Multi-Keyword Ranked Search Techniques over Encrypted Cloud Data

“…This technique is used iteratively to dispense these nodes ID numbers ranging from 1 to N. This assignment is anonymous in that the identities received are strange to the other members of the group. In [6], obtainable and new algorithms for assigning anonymous IDs are examined with respect to trade-offs between communication and Computational requirements. These new algorithms are built on top of a secure sum data mining process using Newton's identities and Sturm's theorem.…”

“…Particularly, we use internal data correspondence, i.e., the figure of query keywords appearing in a document, to appraise the similarity of that document to the search query in coordinate matching principle. Each document is connected with a binary vector as a sub index where each bit represent whether analogous keyword is contained in the document [6] The search reservation is also describe as a dual vector where each bit means whether corresponding keyword appears in this search request, so the similarity could be exactly measured by inner product of query vector with information vector. However, directly outsourcing data vector or query vector will infringe index privacy or search privacy.…”

“…User has the privilege to upload, download and edit data. User's edit request is also served for a fastidious part of the file instead of retrieve the whole file [6]. …”

“…Google search), data users may tend to provide a set of keywords instead of only one as the indicator of their search interest to retrieve the most applicable data. Along with the privacy of data and efficient penetrating schemes, real privacy is obtained only if the user's identity remains hidden from the Cloud Service Provider (CSP) as well as the third party user on the cloud server [6]. In cloud compute data possessor are aggravated to farm out their multifaceted data organization systems from local sites to the marketable public cloud for superior give and economic savings.…”