N-Fmoc-α-sulfo-β-alanine: a versatile building block for the water solubilisation of chromophores and fluorophores by solid-phase strategy.

International audienceAn easy and efficient solid-phase synthesis strategy to obtain rapidly water-soluble chromophores/fluorophores in highly pure form has been developed. This first successful use of N-Fmoc-α-sulfo-β-alanine as a SPPS building block opens the way to the future development of promising direct "on-resin" peptide labelling and water-solubilising methods

Solid-Phase Peptide Synthesis Using a Four-Dimensional (Safety-Catch) Protecting Group Scheme

Peptides of importance to both academia and industry are mostly synthesized in the solid-phase mode using a two-dimensional scheme. The so-called Fmoc/tBu strategy, where the groups are removed by piperidine and TFA, respectively, is currently the method of choice for peptide synthesis. However, as the molecular diversity of cyclic and branched peptides becomes a challenging interest, a high level of orthogonal dimensionality is required, such as through triorthogonal protection schemes. Here we present a fourth category of orthogonal protecting groups that are stable under cleavage conditions, including the TFA treatment that removes the tBu-based groups. At the end of the synthetic process and upon some chemical manipulation, the groups in this fourth category were removed with TFA. This new concept of protecting groups could facilitate the synthesis and manipulation of difficult peptides.This work was partially funded by the National Research Foundation (NRF) (Blue Sky’s Research Program no. 120386). We thank Geraldo. A. Acosta, University of Barcelona, for the HRMS and NMR characterization.Peer reviewe

Solid-Phase Synthesis of an "Inaccessible" hGH-Derived Peptide Using a Pseudoproline Monomer and SIT-Protection for Cysteine

The solid-phase peptide synthesis (SPPS) of the C-terminal sequence of hGH with one extra Tyr attached to its N-terminus (total of 16 residues with a disulfide bridge) has been accomplished for the first time by optimizing several synthetic parameters. First of all, the two Ser residues (positions 9 and 13 of the molecule) have been introduced as a single amino acid, Fmoc-Ser(ψMe,Mepro)-OH, demonstrating that the acylation of these hindered moieties is possible. This allows us to avoid the use of the corresponding dipeptides, Fmoc-AA-Ser(ψMe,Mepro)-OH, which are very often not commercially available or very costly. The second part of the sequence has been elongated via a double coupling approach using two of the most effective coupling methods (DIC-OxymaPure and HATU-DIEA). Finally, the disulfide bridging has been carried out very smoothly by a chemoselective thiol-disulfide interchange reaction between a SIT (sec-isoamyl mercaptan)-protected Cys residue and the free thiol of the second Cys. The synthesis of this short peptide has evidenced that SPPS is a multifactorial process which should be optimized in each case.The authors wish to thank Yoav Luxembourg (Luxembourg Biotechnology, Nes Ziona, Israel) for a generous gift of coupling reagents.Peer reviewe

The effect of inhaled nitric oxide on the course of extracorporeal membrane oxygenation and the occurrence of hemorrhagic complications.

Item does not contain fulltextThis study evaluated the relation between prior inhaled nitric oxide (iNO) and the time to initiation and duration of treatment with veno-arterial extracorporeal membrane oxygenation (ECMO) and the occurrence of hemorrhagic complications. A retrospective study was conducted in 59 human newborns treated for respiratory insufficiency with ECMO over a 5-year period. Patients received iNO before ECMO (iNO group) or not (control group). Both groups were compared for patient characteristics, postnatal age at the initiation of ECMO, duration of ECMO treatment, and hemorrhagic complications. There were no significant differences between the iNO group and the control group for patient characteristics and medication use before the ECMO treatment, except for norepinephrine. There was no significant difference for postnatal age at the initiation of ECMO and mean duration of ECMO treatment. We found no statistically significant difference in hemorrhagic complications between both groups. This persisted after correction for diagnosis and ECMO run-time in linear logistic regression analysis. Inhaled nitric oxide before ECMO did not result in a significant delay in the initiation of ECMO or longer duration of the ECMO. There was no significant relationship between the use of prior iNO and the occurrence of hemorrhagic complications during the ECMO treatment