Scientists from the Council for Scientific and Industrial Research (CSIR) - Indian Institute of Integrative Medicine, Jammu and the Academy of Scientific and Innovative Research, New Delhi have now synthesized hybrid protein sequences with antimicrobial properties, by using a mixture of natural and synthetic analogues of amino acids – the building blocks of proteins.
Various multicellular organisms like fishes, frogs and mammals produce short sequences of proteins called antimicrobial peptides that are capable of acting as natural antibiotics against a host of pathogens. These antimicrobial peptides, generally 12-50 amino acids long, are really diverse in terms of their sequence of amino acids. Drawing inspiration from the antimicrobial peptides, scientists have been trying to come up with artificial varieties of such proteins in order to help develop newer antibiotics against specific microbes.
One such strategy employed by them is the use of beta- and gamma-amino acids. Almost all of the amino acids found in living organisms are an alpha-amino acid, which means that its constituent atoms are arranged in a specific configuration, which is recognised by all living organisms. If we tweak the configuration of these individual amino acids in certain ways, it results in a slightly different configuration of amino acids, which are called beta-amino acids and gamma-amino acids. These beta- and gamma-amino acids cannot be properly degraded and processed by most microbes, like bacteria, fungi, yeasts and protozoa, and can therefore serve as potent antibiotic against these pathogens.
For their study, the researchers synthesized several such hybrid antimicrobial peptides by using a mixture of alpha, beta and gamma amino acids. They further studied the properties of these hybrid peptides, and found that a particular hybrid peptide made up of alpha and gamma amino acids was very effective against the pathogens like Pseudomonas aeruginosa and Staphylococcus aureus. The researchers also tested this peptide for its effect on human cells, and found that it was one of the least harmful peptides among all the hybrid peptides they had synthesized.
Given that both P. aeruginosa and S. aureus are known to cause several serious infections like pneumonia and sepsis, and are frequently known to develop antibiotic resistance, the discovery of these novel antimicrobial peptides could be an extremely useful tool for clinicians.