The process of molecular formation determines protein function

The Virginia Tech team is led by two biochemical graduate students, isolating proteins responsible for the formation of iron-sulfur groups, while observing the necessary protein interactions in the living body - at one point. cell. They grasped the intermediate pathway and observed protein interactions between the two main factors that form the iron-sulfur group.

Iron-sulfur groups are crucial to life on earth. They are necessary for protein function in some cellular processes, such as human respiration as well as other organisms or photosynthesis in plants. Callie Raulfs of Christiansburg said: 'But we still don't understand how the Fe-S molecule is created or linked. It does not happen naturally. It must be adjusted '.

Diseases such as Friedrich disorder and some forms of anemia are the result of malfunction of iron - sulfur group (ISC).

Using genetic and biochemical methods, Ph.D. students Raulfs and Ina P. O'Carroll, in Tirana, Albania, have isolated components of the ISC structure in the process of iron-sulfur formation. O'Carroll said: 'This work provides insight into the steps involved in the formation of iron-sulfur groups, contributing to explain how the iron and sulfur molecules are synthesized in the world. plan '.

Research on 'The process of forming iron - sulfur in living organisms' by Raulfs, O'Carroll; post-doctoral collaborators at Virginia Tech, Patricia C. Dos Santos from Brazil and Mihaela-Carmen Unciuleac from Romania; with Dennis R. Dean from Blacksburg, professor of biochemistry and director of Fralin Biotechnology Center at Virginia Tech, was published in the Proceedings of the National Academy of Science (PNAS) online edition of 16-20 months 6, 2008.

On the picture is the molecular structure of a group of 4 iron - 4 sulfur, sulfur yellow and blue iron.(Photo: Callie Raulfs)

Previous studies by Dean and colleagues have demonstrated that proteins can assemble molecular groups from in vitro components - that is, outside the organism. In the study of nitrogen agglutination systems 10 years ago, Dean's experimental group were the first to discover the ISC protein. Now Dean's students, Raulfs and O'Carroll, are the first to observe the formation of protein in living tissue in living organisms.

O'Carroll said: 'What's interesting is that we've found a way to observe the ISC protein in their innate environment with an attached molecular group. This system also allows us to capture different stages in this process. '

Students isolated three intermediates of ISC proteins involved in intercellular synthesis - or the process of forming molecular groups.

Instead of superposing proteins by placing them in E. coli, Virginia Tech's team used Azotobacter vinelandii, a soil-loving bacterium capable of concentrating nitrogen in the air, to meet protein's natural conditions. ISC. Raulfs was the first to isolate a protein with an attached group of molecules that provided living evidence of the two proteins combined to form a molecular group. He said: 'Vinelandii grows rapidly and keeps oxygen from entering the inner cell, which is important because oxygen can destroy the Fe-S group'.

O'Carroll said: 'Since we isolate proteins from cells, we can observe the interaction between Fe-S group-forming proteins. We were able to isolate a complex between two major factors in iron - sulfur formation, molecular group formation (IscU) and sulfur transporter protein (IscS). "

O'Carroll said the method is to add a histidine amino acid to the protein ISC 'from which we can pull the protein out of the cell'.

O'Carroll explains: 'Because we take proteins that contain molecular groups out of cells that contain all the other necessary proteins at the physiological level, we can see what goes with this protein. The interesting thing in this case is that we see a large amount of an iron - sulfur group, IscS 'protein.

This study marks the first time scientists have been able to observe ISC proteins from the balanced environment of natural cells.

Next, they plan to find a way to determine the role of each gene in the ISC protein genome, which aims to understand the effect of each gene on this synthesis. O'Carroll stressed: 'Our goal is to identify the events and order of the ISC formation process, from which we can understand how cells create molecular groups and then deliver them to the protein pepper'.

Researchers are developing a system that allows other scientists to use it to study proteins.