We all are aware of the fact that organisms can live in diverse environment conditions like hot, cold and high salinity. However it is hard to believe that there are organisms which can survive in boiling waters of hot springs or in highly acidic environments. Archaea which look like bacteria in size and shape are these strange organisms, which can survive in such extreme environmental conditions. Archaea however differs from bacteria in their genetic and biochemical make up and was recognized as a domain of life distinctly different from other two domains bacteria and Eukaryota (plants, animals, fungi & protists).
Lectins are carbohydrate binding proteins which were first reported from plants. Now they are found in all types of organisms. Lectin found in different group of organisms differs widely in structure. The ability to specifically bind carbohydrate is the only similarity among different lectins. Archaea were discovered as constituting a new domain of life only recently and so number of studies in archaea is less in comparison to the other two domains of life.
Researchers from Molecular Biophysics Unit, Indian Institute of Science, Bangalore under the guidance of Prof. M. Vijayan have reported the first significant findings on archeal lectins. They studied 165 archeal genomes from 78 species. After comparison of domain structure, sequence similarity and binding sites with the already reported lectins from other domains of life, they identified 46 novel archeal lectins. The result shows presence of at least six classes of lectins similar to bacteria and eukaryotes. This first comprehensive bioinformatic study forms the strong background for further research in this relatively unexplored field. Prof. Vijayan along with his colleague Prof. Surolia started working on lectins in the late 1970’s when the area was just beginning to blossom. Prof. Vijayan used the crystallographic studies on lectins and he is one of the pioneers to nurture macromolecular crystallographic studies in India.
“The role of carbohydrates in food and as part of structure of organisms (particularly plants) has been well known for a very a long time. Only a few decades ago, it was realized that most of the interactions on the cell surface are mediated by carbohydrates. Protein carbohydrate interactions are therefore important in biological recognition processes. Lectins are quintessential
carbohydrate binding proteins and they are important tools for understating protein-carbohydrate interactions”. Said Prof. Vijayan. The identification of lectins in archaea has considerable evolutionary significance. It shows that lectins are ancient molecules and came into existence before the three domains of life diverged.
About the authors:
M. Vijayan is the Albert Einstein Professor at Indian Institute of Science, Bangalore Karnataka, India. K. V. Abhinav is a PhD research scholar and Ebenezer Samuel was a postdoctoral fellow at Prof. Vijayan’s Lab.
About the study
The paper appeared online in the journal “PROTEINS: Structure, Function and Bioinformatics”