Procyclins also known as procyclic acidic repetitive proteins or PARP
are
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
s developed in the surface coating of ''
Trypanosoma brucei
''Trypanosoma brucei'' is a species of parasitic Kinetoplastida, kinetoplastid belonging to the genus ''Trypanosoma'' that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is excl ...
'' parasites while in their
tsetse fly
Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies) are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Gloss ...
vector.
The cell surface of the bloodstream form features a dense coat of
variable surface glycoproteins (VSGs) which is replaced by an equally dense coat of procyclins when the parasite differentiates into the procylic form in the tsetse fly midgut.
There are six or seven procyclin genes that encode unusual proteins with extensive tandem repeat units of
glutamic acid
Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α- amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can ...
(E) and
proline
Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the p ...
(P), referred to as EP repeats (
EP1,
EP1-2,
EP2,
EP2-1,
EP3,
EP3-2,
EP3-4), and two genes that encode proteins with internal pentapeptide GPEET repeats (
GPEET2
Procyclins also known as procyclic acidic repetitive proteins or PARP are proteins developed in the surface coating of ''Trypanosoma brucei'' parasites while in their tsetse fly vector. The cell surface of the bloodstream form features a ...
).
EP1 is a 141 amino acids protein and EP2 is a 129 AA protein. Both proteins have their coding genes situated on chromosome 10. GPEET2 is a 114 AA protein and EP3-2 is 123 AA protein with genes situated on chromosome 6.
See also
*
Coat protein (disambiguation)
References
External links
Kinetoplastid proteins
Parasitic excavates
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