Researchers at the Technion have deciphered the atomic structure of an important anti-bacterial peptide in the human immune system and discovered that it forms fibers with a special structure. In their estimation, the findings may lead to the formation of similar artificial particles that will be used to specifically target infections and even cancer cells. The discovery was published yesterday in the journal Nature Communications.
Peptide is a short chain of amino acids. Unlike proteins, which usually contain many hundreds of amino acids, peptides contain at most dozens of such acids. One of the important peptide groups is the antimicrobial peptide group (AMPs), which is the subject of the present study. This group plays a significant role in the innate immune system and helps it deal with various bacterial infections.
Technion researchers, Prof. Meital Landau and doctoral student Yitzhak Engelberg from the Faculty of Biology, focused in the current study on an active derivative of the antimicrobial peptide LL-37 (17-29) which is found in the human body and helps it fight various bacteria. In a study conducted at the Technion and particle accelerators in Europe, the two found that one of the means used by this peptide in killing bacteria is a unique protein fiber that is highly stable and resistant to high heat. The researchers mapped the form of self-assembly of the fiber – a long, film-like structure that exhibits great stability in hostile conditions and attachment to bacterial cells that allows it to attack the bacteria from zero range.
Following the decipherment of the unique structure of the fiber, Engelberg and Prof. Landau propose a new concept for designing resistant and stable artificial antibacterial peptides, which will in some cases replace antibiotic treatment. This is against the background of the fact that antibiotic treatment, which has indeed saved the lives of hundreds of millions in the last hundred years, causes the development of bacterial resistance that impairs its effectiveness. As is well known, many deaths in hospitals today are caused by infection with antibiotic-resistant bacteria – resistance that developed as a result of the bacteria being exposed to high doses of broad-spectrum antibiotics.
Peptides are now considered a great therapeutic promise because in at least some cases they are able to neutralize the population of harmful bacteria (pathogens) without causing the formation of bacterial resistance to treatment. Many research groups around the world are involved in the development of peptides for medical purposes, and the engineering challenges are many: efficiency, selectivity, adaptation to body tissues (bioavailability), storage stability (shelf life) and stability in the body after ingestion.
According to Prof. Landau, the current study is an important step in achieving these goals. The atomic and molecular structure of natural peptides, deciphered in the present study, will make it possible to produce similar structures that will be used as a skeleton or packaging for various applications in biomedical engineering, regenerative medicine, biotechnology and more.
Deciphering the complex structure of the protein fiber was based on research work at the DESY particle accelerators (Germany) and ESRF (France) and at the Technion Centers: The Technion Center for Structural Biology, Lori Lokii Interdisciplinary Center for Life Sciences and Engineering, Micron Microscopy Center ) And Russell Berrie Electron Microscopy Center of Soft Matter. The study was supported by the National Science Foundation (ISF), the Ministry of Science and Technology and the Israel-US Cooperation Fund (BSF).
The Israeli Microscopy Association recently announced that it will award the Margolis Prize for 2020 to doctoral student Yitzhak Engelberg, due to the research breakthrough described in the current article. The award committee noted that the discovery is an “impressive achievement in studying the structure of a human antimicrobial peptide” and that it is expected to lead to diverse applications in biotechnology, nanotechnology, antibacterial drug production, tissue restoration and more.
To the scientific article in Nature Communications