Evolutionary Aspects of Selenium Binding Protein (SBP)

Area of Science:

• Biochemistry
• Evolutionary Biology
• Molecular Biology

Background:

• Selenium-binding proteins (SBPs) are a ubiquitous family, with SBP1 recently identified as a plant stress response regulator.
• SBP1's function as a methanethiol oxidase is known, but its precise role requires further clarification.
• In mammals, SBPs are implicated in anti-carcinogenesis, redox modulation, and detoxification.

Purpose of the Study:

• To investigate the functional potential and evolutionary trajectory of conserved motifs within Selenium-binding proteins (SBPs).
• To understand the evolutionary origins and diversification of SBP sequence motifs across different phyla.

Main Methods:

• Phylogenetic profiling was employed to analyze the distribution and evolution of SBP motifs.
• Construction of a phylogenetic tree to visualize evolutionary relationships and motif differentiation.

Main Results:

• SBPs are absent in fungi and most non-eukaryotic organisms.
• Characteristic SBP motifs, including CSSC and CC, show distinct evolutionary patterns.
• The CC motif is conserved in plants and modified to CxxC in animals, while CSSC motifs are modified in Acidobacteria, Fungi, and Archaea.
• SBP motifs primarily emerged in Archaea and Bacteria, with subsequent retention and modification in Animals and Plants.

Conclusions:

• Selenium-binding proteins likely originated in bacteria, potentially functioning as methanethiol oxidases.
• The evolution of SBP motifs reflects significant diversification events across major domains of life.
• Understanding SBP evolution provides insights into their diverse biological roles, from stress response to metabolic regulation.