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Inhibition of Melanization by a Parasitoid Serine Protease Homolog Venom Protein Requires Both the Clip and the Non-Catalytic Protease-Like Domains.

Thomas P, Asgari S - Insects (2011)

Bottom Line: Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny.Similar to other SPHs, Vn50 consists of a clip and a protease-like (SPL) domain.Protein modeling demonstrated that Vn50 has a very similar structure to known SPHs and functional analysis of Vn50 domains expressed in insect cells indicated that neither of the domains on its own has an inhibitory effect on melanization.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, The University of Queensland, St. Lucia QLD 4072, Australia. pune.thomas@uq.edu.au.

ABSTRACT
Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny. Among these are venom proteins which have been shown to play crucial roles in host regulation. A serine protease homolog (SPH)-like venom protein from Cotesia rubecula was previously shown to inhibit melanization in the host hemolymph by blocking activation of prophenoloxidase to phenoloxidase, a key enzyme in melanin formation. Similar to other SPHs, Vn50 consists of a clip and a protease-like (SPL) domain. Protein modeling demonstrated that Vn50 has a very similar structure to known SPHs and functional analysis of Vn50 domains expressed in insect cells indicated that neither of the domains on its own has an inhibitory effect on melanization.

No MeSH data available.


Related in: MedlinePlus

3D models constructed using ESyPred3D showing the overall predicted tertiary structure of Vn50 based on the crystal structure of serine protease homolog PPAFII from Holotrichia diomphalia. SPL, serine protease-like. C-terminus is shown in red and N-terminus is shown in dark blue.
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f1-insects-02-00509: 3D models constructed using ESyPred3D showing the overall predicted tertiary structure of Vn50 based on the crystal structure of serine protease homolog PPAFII from Holotrichia diomphalia. SPL, serine protease-like. C-terminus is shown in red and N-terminus is shown in dark blue.

Mentions: To investigate if Vn50 has a similar structure to SPHs, tertiary structure predictions were generated using ESyPred3D v1.0 [11]. The model was generated using PPAF-II from H. diomphalia as a template [5]; a protein with 43% identity to Vn50 (E-value = 1e-82). The analysis showed that Vn50 is structurally analogous to PPAFs and forms a similar spatial configuration as PPAF-II (Figure 1). Based on the model, the clip domain in Vn50 contains loops and a central irregular β-sheet forming a clip cleft, like in PPAF-II, which is critical for binding of the protein to proPO. Similarly, the SPL domain of Vn50 had the overall structure of PPAF-II SPL domain with two clefts which may serve as docking sites for protein binding. Similar to other SPHs, in the SPL domain of Vn50 the active serine residue is replaced by a glycine [8]; therefore, Vn50 does not have enzyme activity.


Inhibition of Melanization by a Parasitoid Serine Protease Homolog Venom Protein Requires Both the Clip and the Non-Catalytic Protease-Like Domains.

Thomas P, Asgari S - Insects (2011)

3D models constructed using ESyPred3D showing the overall predicted tertiary structure of Vn50 based on the crystal structure of serine protease homolog PPAFII from Holotrichia diomphalia. SPL, serine protease-like. C-terminus is shown in red and N-terminus is shown in dark blue.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553444&req=5

f1-insects-02-00509: 3D models constructed using ESyPred3D showing the overall predicted tertiary structure of Vn50 based on the crystal structure of serine protease homolog PPAFII from Holotrichia diomphalia. SPL, serine protease-like. C-terminus is shown in red and N-terminus is shown in dark blue.
Mentions: To investigate if Vn50 has a similar structure to SPHs, tertiary structure predictions were generated using ESyPred3D v1.0 [11]. The model was generated using PPAF-II from H. diomphalia as a template [5]; a protein with 43% identity to Vn50 (E-value = 1e-82). The analysis showed that Vn50 is structurally analogous to PPAFs and forms a similar spatial configuration as PPAF-II (Figure 1). Based on the model, the clip domain in Vn50 contains loops and a central irregular β-sheet forming a clip cleft, like in PPAF-II, which is critical for binding of the protein to proPO. Similarly, the SPL domain of Vn50 had the overall structure of PPAF-II SPL domain with two clefts which may serve as docking sites for protein binding. Similar to other SPHs, in the SPL domain of Vn50 the active serine residue is replaced by a glycine [8]; therefore, Vn50 does not have enzyme activity.

Bottom Line: Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny.Similar to other SPHs, Vn50 consists of a clip and a protease-like (SPL) domain.Protein modeling demonstrated that Vn50 has a very similar structure to known SPHs and functional analysis of Vn50 domains expressed in insect cells indicated that neither of the domains on its own has an inhibitory effect on melanization.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, The University of Queensland, St. Lucia QLD 4072, Australia. pune.thomas@uq.edu.au.

ABSTRACT
Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny. Among these are venom proteins which have been shown to play crucial roles in host regulation. A serine protease homolog (SPH)-like venom protein from Cotesia rubecula was previously shown to inhibit melanization in the host hemolymph by blocking activation of prophenoloxidase to phenoloxidase, a key enzyme in melanin formation. Similar to other SPHs, Vn50 consists of a clip and a protease-like (SPL) domain. Protein modeling demonstrated that Vn50 has a very similar structure to known SPHs and functional analysis of Vn50 domains expressed in insect cells indicated that neither of the domains on its own has an inhibitory effect on melanization.

No MeSH data available.


Related in: MedlinePlus