Posts Tagged “PROSITE”

Microbiology, Immunology & Biochemistry Dept.*

Faculty of Pharmacy

Cairo University

Bioinformatics Practical Exam – Winter 2010**
Time allowed: Lab computers will automatically hibernate after 2 hours.***

Target: Assigning the function of the uncharacterized protein O67940_ AQUAE from Aquifex aeolicus ****

A suggested procedure:
1- Get the amino acid sequence of the protein from UniProtKB
— Run it through BLAST to find homologs (related sequences). Do not forget to choose Blastp & PSI-BLAST
— Check the assigned hits (known function & solved crystal structure) which have highest possible similarity (highest score/ highest % id) to your query.
2- Check obtained BLAST alignment of those proteins against your query.
3- Check if the protein belongs to any protein family using PIRSF & COGs
— Check if the protein shares any conserved domain with assigned function using Pfam.
— Using PROSITE the functional site database, check if the protein shares any sequence motifs with other proteins
4- Check if the protein belongs to a superfamily using SCOP database, which provides structural and evolutionary relationships between proteins.
5- As you don’t have the crystal structure of your Aquae protein & you have the structure of the closest assigned protein, use VAST to search & align protein related structures to yours.
6-  Extract homologs.
7- Multiple alignment (structure-guided alignment) using Cn3D
—  Neighbor-joining (NJ) phylogenetic analysis using CDTree
8- Use PDBSum to obtain an overview of the protein–ligand interactions available for your query.
9- Alignment of homologous sequences to identify conserved functional residues.
10- Evidence-based assignment of biological function of query O67940_Aquefix.


* What have I got to lose?!
** I have faith.
*** I can provide that; I know a guy who knows a guy!
**** Frankly, I wanted to pick a different protein, but I hesitated.

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