1. Novel complexes of Co(III) and Ni(II) containing peptide ligands: synthesis, DNA binding and photonuclease activity
C N Sudhamani, H S Bhojya Naik, D Girija, K R Sangeetha Gowda, M Giridhar, T Arvinda Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 24;118:271-8. doi: 10.1016/j.saa.2013.08.074. Epub 2013 Aug 31.
The new cobalt(III) and nickel(II) complexes of the type [M(L)2(H2O)2](n)(+) (where M = Co(III) or Ni(II) ion, n = 3 for Co and 2 for Ni, L = peptides Fmoc. Ala-val-OH (F-AVOH), Fmoc-Phe-Leu-Ome (F-PLOMe) and Z-Ala-Phe-CONH2 (Z-APCONH2)) were synthesized and structurally characterized by FTIR, (1)H NMR, elemental analysis and electronic spectral data. An octahedral geometry has been proposed for all the synthesized Co(III) and Ni(II) metal complexes. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. Detailed analysis revealed that the metal complexes intercalates into the DNA base stack as intercalator. The photo induced cleavage studies shows that the complexes possess photonuclease property against pUC19 DNA under UV-Visible irradiation.
2. High-Quality Conjugated Polymers Achieving Ultra-Trace Detection of Cr2O72- in Agricultural Products
Hui Li, Fei Li, Fang Liu, Xiao Chen, Wenyuan Xu, Liang Shen, Jingkun Xu, Rui Yang, Ge Zhang Molecules. 2022 Jul 4;27(13):4294. doi: 10.3390/molecules27134294.
In view of that conjugated polymers (CPs) are an attractive option for constructing high-sensitive Cr2O72- sensors but suffer from lacking a general design strategy, we first proposed a rational structure design of CPs to tailor their sensing properties while validating the structure-to-performance correlation. Short side chains decorated with N and O atoms as recognition groups were instructed into fluorene to obtain monomers Fmoc-Ala-OH and Fmoc-Thr-OH. Additionally, their polymers P(Fmoc-Ala-OH) and P(Fmoc-Thr-OH) were obtained through electrochemical polymerization. P(Fmoc-Ala-OH) and P(Fmoc-Thr-OH) with high polymerization degrees have an excellent selectivity towards Cr2O72- in comparison to other cations and anions. Additionally, their limit of detection could achieve 1.98 fM and 3.72 fM, respectively. Especially, they could realize the trace detection of Cr2O72- in agricultural products (red bean, black bean, and millet). All these results indicate that short side chains decorated with N and O atoms functionalizing polyfluorene enables the ultra-trace detection of Cr2O72-. Additionally, the design strategy will spark new ideas for the construction of highly selective and sensitive Cr2O72- sensors.
3. Identification of Fmoc-beta-Ala-OH and Fmoc-beta-Ala-amino acid-OH as new impurities in Fmoc-protected amino acid derivatives
E Hlebowicz, A J Andersen, L Andersson, B A Moss J Pept Res. 2005 Jan;65(1):90-7. doi: 10.1111/j.1399-3011.2004.00201.x.
During the manufacture of a proprietary peptide drug substance a new impurity appeared unexpectedly. Investigation of its chemical structure established the impurity as a beta-Ala insertion mutant of the mother peptide. The source of the beta-Ala was identified as contamination of the Fmoc-Ala-OH raw material with Fmoc-beta-Ala-Ala-OH. Further studies also demonstrated the presence of beta-Ala in other Fmoc-amino acids, particularly in Fmoc-Arg(Pbf)-OH. In this case, it was due to the presence of both Fmoc-beta-Ala-OH and Fmoc-beta-Ala-Arg(Pbf)-OH. It is concluded that beta-Ala contamination of Fmoc-amino acid derivatives is a general and hitherto unrecognized problem to suppliers of Fmoc-amino acid derivatives. The beta-Ala is often present as Fmoc-beta-Ala-OH and/or as a dipeptide, Fmoc-beta-Ala-amino acid-OH. In collaboration with the suppliers, new specifications were introduced, recognizing the presence of beta-Ala-related impurities in the raw materials and limiting them to acceptable levels. The implementation of these measures has essentially eliminated beta-Ala contamination as a problem in the manufacture of the drug substance.
