Sequence Analysis of the cAMP-Dependent Protein Kinase Regulatory Subunit-Like Protein From Trypanosoma brucei

Study the N-terminal, C-terminal, and linker regions of the TbPKAr using homology modeling.

The amino acid sequences of the N-terminal, C-terminal, and linker regions of the TbPKAr were individually examined by means of BLAST analysis and in silico secondary structure predictions with several programs.

The TbPKAr C-terminal region, showed a well-folded α/β structure, which consists of two concurrent flattened β-barrel-shaped domains that are separated by an elongated central α-helix similar to its mammalian counterpart, the TbPKAr linker region contains a PKA phosphorylation site and was predicted to be rather disordered. Our analysis also indicated that the TbPKAr N-terminal region lacks a docking/dimerization domain but is enriched in motifs known as leucine-rich repeats (LRR).

The replacement of the docking/dimerization domain by different structural motifs suggests the inability of TbPKAr to form homodimers; however, the function of the TbPKAr N-terminal LRR-containing domain in Kinetoplastidae parasites is still unknown.