What are Protein Domains?
Protein domains are recognized peptide sequences found in proteins that have a specific structure or function attributed to them. [1] Domain analysis allows for the function of a protein to be understood by the domains found in its sequence. [1] Comparisons can be drawn to other proteins with similar domains and known functions. [2] Often, proteins with the same or similar domains may be classified into a protein family, and they frequently possess similar cellular functions. [1]
GLI3 Protein Domains
Figure 1. Protein domains as established by SMART software. Five C2H2 zinc-finger domains are detected in the center of the protein.
Figure 2. Protein domains as established by Pfam software. Only a single C2H2 zinc-finger domain is detected, unlike the five reported by SMART. Not pictured are four zinc-finger domains found to be 'insignificant' by the Pfam algorithm.
C2H2 Zinc-Finger Domain
Zinc-finger domains are a family of relatively short protein motifs that bind to a target molecule. [3] Often the target is zinc, but others bind to different metals or to DNA or RNA substrates. [3] Zinc finger domains are a common feature on transcription factor proteins. [3]
Domain Analysis Among Homologs
Conclusion
The only recognizable protein domains found in GLI3 are C2H2 zinc fingers. These domains are well-conserved across homologous genes, and are used in DNA binding. This aligns with the prior data indicating GLI3's role as a transcription factor controlling the expression of genes during embryonic development. [4] The specificity of DNA binding is controlled by the zinc-finger domains-- as GLI3's function is being explored, determining these domains' roles in its duty as a transcription factor is a promising avenue of experimentation.
References
- EMBL-EBI. (n.d.) Family- and Domain-based protein classification. Retrieved from: https://www.ebi.ac.uk/training/online/course/introduction-protein-classification-ebi/protein-classification/family-and-domain-based-protei
- ProteinStructures.com. (n.d.) Protein Domains and Domain Classification. Retrieved from: https://proteinstructures.com/Structure/Structure/protein-domains.html
- Fedotova, A. A., Bonchuk, A. N., Mogila, V. A., & Georgiev, P. G. (2017). C2H2 Zinc Finger Proteins: The Largest but Poorly Explored Family of Higher Eukaryotic Transcription Factors. Acta naturae, 9(2), 47-58.
- Carballo, G. B., Honorato, J. R., de Lopes, G. P. F., & Spohr, T. C. L. d. S. e. (2018). A highlight on Sonic hedgehog pathway. Cell Communication and Signaling, 16(1), 11. doi:10.1186/s12964-018-0220-7
Images
Header: https://scitechdaily.com/proteins-engineered-with-predictable-structures/
Image 1: https://pdb101.rcsb.org/motm/87
Image 1: https://pdb101.rcsb.org/motm/87
This web page was produced as an assignment for Genetics 564, an undergraduate capstone course at UW-Madison.