Examples are cerebrosides and gangliosides.Ī sterol lipid (e.g. sphingosine and ceramides) backbone and sugar residue(s) linked by a glycosidic bond. Examples of phospholipids include phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, lecithin, plasmalogens and sphingomyelins.Ī sphingolipid is a lipid made up of a sphingoid base (e.g. Phospholipids are amphipathic compounds in a way that the ‘head’ is hydrophilic and the lipophilic ‘tail’ is hydrophobic. It is also involved in metabolism and cell signaling. In animals, the fatty acid component is largely saturated.Ī glycerophospholipid, or simply phospholipid, is a type of lipid that is an essential component of many biological membranes, particularly the lipid bilayer of cells. In plants, they are typically found in plant cell membrane where the fatty acids are mostly unsaturated. The triglyceride is a major component of animal and plant oils and fats. The three hydroxyl groups of glycerol in triglyceride are all esterified. The triglyceride is an energy-rich compound consisting of a glycerol and three fatty acids (thus, the name). One of the most commonly known glycerolipids is the triglyceride (also referred to as triacylglycerol). Examples include lauric acid, palmitic acid, etc.Ī glycerol is a type of lipid made up of a glycerol linked esterically to a fatty acid. Saturated fatty acids are fatty acids that lack unsaturated linkages between carbon atoms. Examples of unsaturated fats are monounsaturated fatty acid, polyunsaturated fat, omega fatty acids, etc. The unsaturated fatty acids may be further grouped into monounsaturated fatty acid and polyunsaturated fatty acid. Fatty acids may be classified into (1) unsaturated fatty acid and (2) saturated fatty acids. It is represented by R-COOH, where R stands for the aliphatic moiety and COOH as the carboxylic group (making the molecule an acid). It is produced by the breakdown of fats (usually triglycerides or phospholipids) through a process called hydrolysis. It pertains to any long chain of hydrocarbon, with a single carboxylic group at the beginning and a methyl end, and aliphatic tail. Specifically, the Leu-containing diastereomeric peptide micellized vesicles and possibly bacterial membranes while the Ile-containing diastereomeric peptide fused model membranes and irregularly disrupted bacterial membranes.A fatty acid is a subunit of fats, oils, and waxes. Furthermore, efficient increase in membrane permeability can proceed through different mechanisms. Importantly, we found a direct correlation with the diastereomers between hydrophobicity and propensity to form a helical/distorted-helix and activity (induced membrane leakage and antibacterial activity), despite the fact that they contained 30% D-amino acids.
While hemolytic activity was drastically reduced, the spectrum of antibacterial activity was preserved or increased. In contrast, the diastereomeric peptides were monomeric and unstructured in solution, but they adopted distinct structures upon membrane binding. The Val- and Leu-containing peptides were hemolytic but inactive toward most bacteria tested. Among this group only the Leu containing peptide was hemolytic and highly active on most bacteria tested. Most of the L-amino acid peptides oligomerized and adopted distinct structures in solution and in a membrane mimetic environment. The effect of the aliphatic amino acids on the biological activity, binding, structure, membrane localization, and mode of action of these peptides was investigated.
To this end, we synthesized a series of model amphipathic all L-amino acid peptides and their diastereomers with the sequence KX(3)KWX(2)KX(2)K, where X = Gly, Ala, Val, Ile, or Leu. However, a systematic analysis of the contribution of multiple hydrophobic amino acids to these steps have been hindered by the propensity of many peptides to aggregate and become inactivated in solution. Antimicrobial peptides serve as an important model for studying the details of these initial steps. The initial stages leading to the binding and functioning of membrane-active polypeptides including hormones, signal sequences, and lytic peptides are mainly governed by electrostatic attraction and hydrophobic partitioning between water and lipid bilayers.