Final answer:
Antimicrobial peptides (AMPs) are small, positively charged peptides that are part of the innate immune system. They are amphipathic, enabling them to disrupt the membranes of pathogens, and are produced in response to infections. AMPs have broad-spectrum antimicrobial activity and can modulate the immune response.
Step-by-step explanation:
What are Antimicrobial Peptides (AMPs)?
Antimicrobial peptides (AMPs) are small cationic peptides that are part of the innate immune system and offer a first line of defense against pathogenic infections. They typically contain 15-45 amino acid residues and are charged positively at physiological pH due to the presence of lysine (Lys) and arginine (Arg) residues. AMPs are amphipathic, meaning they contain both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, allowing them to interact with the lipid membranes of pathogens. A defining feature of AMPs is their ability to target and interact with microbial membranes leading to permeabilization and potentially to cell death.
Why are they produced?
AMPs are produced as a response by the host to microbial infections. They are found in various species, indicating their importance in survival and host defense across different ecological niches.
Characteristic Features and Effects on Intracellular Processes
The amphipathic character of AMPs enables them to insert into microbial membranes, disrupt their integrity, and ultimately kill the pathogen. This mechanism relies on the balance between hydrophobic and electrostatic effects. Their broad-spectrum antimicrobial activity covers bacteria, fungi, and viruses, and their role in modulating the host's immune response is also being explored. AMPs can be classified into families based on structure, such as α-helical peptides, peptides with disulfide bridges, or peptides rich in specific amino acids like proline and arginine.