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Extremely diverged actin proteins in Plasmodium falciparum
J G Wesseling1, M A Smits, J G Schoenmakers
1Laboratory of Molecular Biology, Faculty of Science, University of Nijmegen, The Netherlands.
Molecular and Biochemical Parasitology
|August 1, 1988
Summary
Malaria parasites Plasmodium falciparum possess two distinct actin proteins, pf-actin I and pf-actin II. Pf-actin II exhibits significant sequence divergence, suggesting unique evolutionary pathways in protozoan actin genes.
Area of Science:
- Molecular Parasitology
- Protein Evolution
- Genomics
Background:
- The Plasmodium falciparum actin protein (pf-actin I) nucleotide sequence was previously characterized.
- The human malaria parasite genome is known to encode actin proteins, essential for cellular functions.
Purpose of the Study:
- To identify and characterize a second actin protein (pf-actin II) in Plasmodium falciparum.
- To analyze the evolutionary relationships of pf-actin II with other known actin proteins.
Main Methods:
- Nucleotide sequence analysis of the complementary DNA coding for pf-actin II.
- Amino acid sequence determination and comparison with pf-actin I and other eukaryotic actins.
Main Results:
- Evidence for a second actin protein, pf-actin II, in Plasmodium falciparum.
- Pf-actin II displays substantial amino acid sequence divergence from known actins, including pf-actin I.
- The lowest inter-species similarity observed between two actins within the same species (Plasmodium).
Conclusions:
- Protozoan actin gene evolution suggests a common ancestor for sporozoa and ciliated protozoa, excluding amoebae.
- Actin sequences in protozoa appear less conserved during evolution compared to other eukaryotic lineages.
- The unique nature of pf-actin II highlights the diverse evolutionary strategies of actin genes in parasites.