Crystal state conformation of three model monomer units for the β-bend ribbon structure

The molecular and crystal structures of three compounds, representing the repeating units of the β-bend ribbon (an approximate 310-helix, with an intramolecular hydrogen-bonding donor every two residues), have been determined by x-ray diffraction. They are Boc-Aib-Hib-NHBzl, Z-Aib-Hib-NHBzl, and Z-L-Hyp-Aib-NHMe (Aib, α-aminoisobutyric acid; Bzl, benzyl; Boc, t-butyloxycarbonyl; Hyp, hydroxyproline Hib, α-hydroxyisobutyric acid; Z, benzyloxycarbonyl). The two former compounds are folded in a -bend conformation: type III (III′) for Boc-Aib-Hib-NHBzl, while type II (II′) for the Z analogue. Conversely, the structure of Z-L-Hyp-Aib-NHMe, although not far from a type II β-bend, is partially open

Differences arising in human neutrophil activation passing from N-formyl to N-acetyl-oligopeptides.

N-formyl- and N-acetyl-peptides were synthesized and compared in order to understand which features can best elicit biological responses. The behavior of N-formyl-peptides confirms the previously found sequential obligations in the residues, while acetyl-derivatives do not seem suitable for an efficacious stimulation of human neutrophils

The importance of the methionine configuration in for-Met-Leu-Phe-OMe biological activities.

for-D-Met-L-Leu-L-Phe-OMe was synthesized in order to understand the importance of the methionine configuration on human neutrophil biological activity. Our results show that both chemotactic response and lysozyme release are lower than those of the parent fMLP-OMe, indicating that the specific receptor pocket possesses a well-located, restricted positive area that does not completely face the D-Met residue. The triggering of superoxide anion production does not seem to be sensitive to this variation of the configuration

An exhaustive insight into the pocket charge features of the methionine receptor using fMLP analogs.

Neutrophils play a key role as primary phagocytic cells, because they constitute the first line of defense against bacterial invasion, and contribute to inflammatory processes. the goal of the study herein reported is to clarify the features peculiar to the methionine receptor pocket. it has widley accepted that the L-Met residue seems to induce optimum chemotactic as well as secretory activities. the synthesised analogs, here reported, have clarified that the positively charged area in the Met pocket is i) narrow in dimension, ii) located at well defined distance from the backbone, and iii) oriented in a specific position, not completely surrounding the internally located said chain

Synthesis and biological activity of a conformationally constrained chemotactic γ-lactam formyl tetrapeptide

The synthesis and biological activity on human neutrophils of for-Met-(γ-lactam)-Leu-Phe-OMe [fM(γl)LP-OMe], an analogue of the chemotactic fMLP-OMe, are reported. The tetrapeptide evidences chemotactic activity as well as superoxide anion production and lysozyme release, although with lower efficacy when compared with the parent tripeptide

CONFIGURATIONAL STUDIES ON VICINAL IMINO OXIMES

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Composizione bromatologico-nutrizionale di varietà di soia

Sono state caratterizzate diverse varietà di soia, sia dal punto di vista chimico bromatologico sia per quanto riguarda la componente funzionale, in particolare gli antiossidanti

Base-Promoted Cyclocoupling Reaction of 2-Bromopropanamides and 2-Bromoacetamides with DMF

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CONTROL OF ENANTIOSELECTIVITY IN THE FORMATION OF A MODEL ALANINAMIDE FROM A 2-BROMOPROPANAMIDE

Reactions of (R)- or (S)-2-chloro- or bromopropanamides 1,2 and related compounds with benzylamine in the presence of AlCl3, Ag2O, or a lipase (CCL) in an organic solvent, are described. N,N′-Dibenzylalaninamide 6 of either optical activity is obtained from optically active 2 by proper use of Ag2O