Peptide interesting/important

A wide variety of a-tnfluoromethyl a-amino acids are readily available from the reaction of 5-fluoro-4-tnfluoromethyl-l,3 azoles with allylic alcohols [138, 139] a-Tnfluoromethyl-subsumted a-amino acids show anubactenal and antihy pertensive activity Some are highly specific enzyme inhibitors (suicide inhibitors) and may be important as bioregulators [140] Furthermore, they are interesting candidates for peptide modification... 

Human tumor necrosis factor (TNF) (Fig. 1) is a hormone-like proinflammatory peptide belonging to the group of cytokines. It is mainly produced by cells of the immune system in response to infection, inflammation, or cell damage. Disregulated TNF is an important factor in many pathological situations, like sqDsis, rheumatoid arthritis, inflammatory bowel disease (Crohn s disease), and Cachexia. The cytotoxic activity of TNF is of interest in development of new antitumoral strategies. 

Other interesting examples of proteases that exhibit promiscuous behavior are proline dipeptidase from Alteromonas sp. JD6.5, whose original activity is to cleave a dipeptide bond with a prolyl residue at the carboxy terminus [121, 122] and aminopeptidase P (AMPP) from E. coli, which is a prohne-specific peptidase that catalyzes the hydrolysis of N-terminal peptide bonds containing a proline residue [123, 124]. Both enzymes exhibit phosphotriesterase activity. This means that they are capable of catalyzing the reaction that does not exist in nature. It is of particular importance, since they can hydrolyze unnatural substrates - triesters of phosphoric acid and diesters of phosphonic acids - such as organophosphorus pesticides or organophosphoms warfare agents (Scheme 5.25) [125]. 

The way that Pn peptides self-assemble is important for polypeptides and proteins amyloid-type structures are believed to have the same core stmcture, and in fact the propensity to self-assemble in this manner is hypothesized to be a general property of polypeptides [52]. It is therefore unsurprising that systems featuring this motif are common. In recent years, a push towards the use of peptide-based self-assembled materials has led to increasing interest in extending their functionality by derivatising them. 

It is important to emphasize that this lattice database is highly idealized compared to real databases. Unlike the lattice database, real databases cannot be treated as thermodynamic ensembles of protein-ligand complexes equilibrated at room temperature [33,34]. Two of the more straightforward reasons are mentioned here. First, real databases are inherently biased toward strong binders (K < 10 pM), because weak binders are difficult to crystallize and of lesser interest. Second, as mentioned above, real databases are not composed of a representative selection of proteins and ligands, and their compositions are biased toward peptide and peptidomimetic inhibitors and certain protein superfamilies. In contrast, because only one protein and four ligand types are used, the lattice database should have representative ligand compositions. 

Amphipathic peptides contain amino acid sequences that allow them to adopt membrane active conformations [219]. Usually amphipathic peptides contain a sequence with both hydrophobic amino acids (e.g., isoleucine, valine) and hydrophilic amino acids (e.g., glutamic acid, aspartic acid). These sequences allow the peptide to interact with lipid bilayer. Depending on the peptide sequence these peptides may form a-helix or j6-sheet conformation [219]. They may also interact with different parts of the bilayer. Importantly, these interactions result in a leaky lipid bilayer and, therefore, these features are quite interesting for drug delivery application. Obviously, many of these peptides are toxic due to their strong membrane interactions. 

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