This document discusses profilin, a multifunctional protein found in eukaryotes and prokaryotes. It is involved in poly-proline binding, actin polymerization, and PIP2 interaction. The study aims to compare the sequence, structure, and conserved domains of profilin proteins in apicomplexan parasites and model organisms. Profilin sequences were retrieved from databases and aligned using BLAST and ClustalW. Secondary structure was predicted using PSIPRED, and tertiary structure was modeled using PHYRE2. The results show profilin's actin-binding domains are highly conserved, while poly-proline binding sites are more variable. Profilin proteins were more conserved

1. By Anil Kumar
B.Sc.(Hons.) III Bioinformatics
Roll No: 6208
PUPIN: 17511001389

2.  Profilin is a multifunctional single domain protein
found in prokaryotes as well as eukaryotes.
 The major functions of profilin are poly-proline
binding, polymerization of actin protein and PIP2
interaction.
 The latter interaction keeps profilin in deactivated
state and the former two interactions facilitate actin
dynamics.

3.  Profilin protein promotes actin polymerization by
exchanging ATP for ADP on monomeric actin and
delivering ATP-actin to growing filament of barbed
ends
 The profilin protein has five isoforms found in
mammals: Profilin I, Profilin IIa, Profilin IIb, Profilin
III and Profilin IV.
 Apicomplexans is a group of parasitic protists that are
responsible for causing diseases in human beings like
malaria, toxoplasmosis, etc.

4. To study the functional interactions of Profilin protein with other
proteins
To study the conserved regions of Profilin protein in apicomplexan
species, model organisms and human
To compare the secondary and tertiary structure of profilin protein in
apicomplexan species and selected model organisms

5. PROCEDURE
Profilin Protein sequence was retrieved from NCBI Protein Databse
Conserved domains were found using NCBI CDD
BLASTp was performed to retrieve similar sequences
Conserved regions were found by MSA between profilin sequence of
different species using ClustalW Tool
Phylogenetic trees were constructed
Secondary and tertiary structure were compared

7. Proteins with
maximum similarity
Tool Used: BLASTp

8. Since BLASTp using Profilin
sequence of T.gondii could not
retrieve model organism and
human sequences a organism
specific BLASTp was done using
S.cerevisiae profilin sequence.
The following selected model organisms
were considered: D.melnogaster,
C.elegans, A.thaliana and M.musculus
and Homo sapiens.

9. Organism specific BLASTp
Result.

10. Poly-proline binding site Actin Interaction site

12.  MSA of Model Organisms:-
Poly-proline binding site Actin Interaction site

14.  Secondary structure elements of selected
Apicomplexan and model organisms were predicted
using PSIPRED.

15. B.bigemin
a
E.tenella

16. P.yoell
i
T.gondi
i

17. A.thalian
a
C.elegan
s

18. M.musculu
s
S.cerevisia
e

19.  Tertiary structure of selected Apicomplexan and
Model organisms was done using online tool PHYRE2.
 It predicts tertiary structure by comparing query
sequence with the database of protein molecules with
confirmed structure.

20. Result 12: Tertiary structure of C.elegans, P.yoell, A.thaliana and M.musculus in
Clockwise manner

21. Result 13: Tertiary structure of S.cerevisiae, T.gondii and B.bigemina in clockwise.

22.  The main function of profilin is actin binding and
actin binding residues were present in the C-terminus
and middle region of profilin protein.
 These regions were also more conserved than other
regions and likely to contain structurally important
residues.
 The poly-proline binding sites were present in the
scarcely conserved N-terminus region.
 Trp residues play prominent role in poly-proline
binding.

23.  The profilin protein of Apicomplexans were conserved
than the model organisms.
 This can be attributed to the fact that Profilin plays a
role in host invasion in Apicomplexans.
 Despite low similarity, the structure of Profilin protein
was found to be highly conserved in the two groups of
organisms.