| 1. |
- Celorio-Mancera, Maria de la Paz, et al.
(författare)
-
Sialome of a Generalist Lepidopteran Herbivore : Identification of Transcripts and Proteins from Helicoverpa armigera Labial Salivary Glands
- 2011
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:10, s. e26676-
-
Tidskriftsartikel (refereegranskat)abstract
- Although the importance of insect saliva in insect-host plant interactions has been acknowledged, there is very limited information on the nature and complexity of the salivary proteome in lepidopteran herbivores. We inspected the labial salivary transcriptome and proteome of Helicoverpa armigera, an important polyphagous pest species. To identify the majority of the salivary proteins we have randomly sequenced 19,389 expressed sequence tags (ESTs) from a normalized cDNA library of salivary glands. In parallel, a non-cytosolic enriched protein fraction was obtained from labial salivary glands and subjected to two-dimensional gel electrophoresis (2-DE) and de novo peptide sequencing. This procedure allowed comparison of peptides and EST sequences and enabled us to identify 65 protein spots from the secreted labial saliva 2DE proteome. The mass spectrometry analysis revealed ecdysone, glucose oxidase, fructosidase, carboxyl/cholinesterase and an uncharacterized protein previously detected in H. armigera midgut proteome. Consistently, their corresponding transcripts are among the most abundant in our cDNA library. We did find redundancy of sequence identification of saliva-secreted proteins suggesting multiple isoforms. As expected, we found several enzymes responsible for digestion and plant offense. In addition, we identified non-digestive proteins such as an arginine kinase and abundant proteins of unknown function. This identification of secreted salivary gland proteins allows a more comprehensive understanding of insect feeding and poses new challenges for the elucidation of protein function.
|
|
| 2. |
- Kozisek, Milan, et al.
(författare)
-
Molecular design of specific metal-binding peptide sequences from protein fragments: Theory and experiment
- 2008
-
Ingår i: Chemistry: A European Journal. - : Wiley. - 1521-3765 .- 0947-6539. ; 14:26, s. 7836-7846
-
Tidskriftsartikel (refereegranskat)abstract
- A novel strategy is presented for designing peptides with specific metal-ion chelation sites, based on linking computationally predicted ion-specific combinations of amino acid side chains coordinated at the vertices of the desired coordination polyhedron into a single polypeptide chain. With this aim, a series of computer programs have been written that 1) creates a structural combinatorial library containing Z(i)-(X)(n)-Z(j) sequences (n = 0-14; Z: amino acid that binds the metal through the side chain; X: any amino acid) from the existing protein structures in the non-redundant Protein Data Bank; 2) merges these fragments into a single Z(1)-(X)(n1)-Z(2)-(X)(n2)-Z(3)-(X)(n3)- ... -Z(j) polypeptide chain; and 3) automatically performs two simple molecular mechanics calculations that make it possible to estimate the internal strain in the newly designed peptide. The application of this procedure for the Most M2+-specific combinations of amino acid side chains (M: metal see L. Rulisek, Z. Havlas J. Phys. Chem. B 2003, 107, 2376-2385) yielded several peptide sequences (with lengths of 6-20 amino acids) with the potential for specific binding with six metal ions (Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+). The gas-phase association constants of the studied metal ions with these de novo designed peptides were experimentally determined by MALDI mass spectrometry by using 3,4,5-trihydroxyacetophenone as a matrix, whereas the thermodynamic parameters of the metal-ion coordination in the condensed phase were measured by isothermal titration calorimetry (ITC), chelatometry and NMR spectroscopy methods. The data indicate that some of the computationally predicted peptides are potential M2+-specific metalion chelators.
|
|
