Zoeken
Zoeken kan via de modus 'eenvoudig zoeken' (één veld) of uitgebreid via 'geavanceerd zoeken' (meerdere velden). Zo kan je bv. zoeken op een combinatie van een auteursnaam (auteur), een jaartal (jaar) en een documenttype.
Boekenmand
Nuttige resultaten kan je aanvinken en toevoegen aan een mandje. De inhoud hiervan kan je exporteren of afdrukken (naar bv. PDF).
RSS
Op de hoogte blijven van nieuw toegevoegde publicaties binnen uw interessegebied? Dit kan door een RSS-feed (?) te maken van jouw zoekopdracht.
nieuwe zoekopdracht
Role of lysine versus arginine in enzyme cold-adaptation: modifying lysine to homo-arginine stabilizes the cold-adapted α-amylase from Pseudoalteramonas haloplanktis
Siddiqui, K.S.; Poljak, A.; Guilhaus, M.; De Francisci, D.; Curmi, P.M.G.; Feller, G.; D'Amico, S.; Gerday, C.; Uversky, V.N.; Cavicchioli, R. (2006). Role of lysine versus arginine in enzyme cold-adaptation: modifying lysine to homo-arginine stabilizes the cold-adapted α-amylase from Pseudoalteramonas haloplanktis. Proteins-Structure Function and Bioinformatics 64(2): 486-501. https://dx.doi.org/10.1002/prot.20989
In: Proteins-Structure Function and Bioinformatics. Wiley-Blackwell: Hoboken. ISSN 0887-3585; e-ISSN 1097-0134
|  |
| Trefwoord |
|
| Author keywords |
psychrophilic; guanidination; structure-function-stability relationship;enzyme kinetics; thermodynamics; bioinformatics |
| Auteurs | | Top |
- Siddiqui, K.S.
- Poljak, A.
- Guilhaus, M.
- De Francisci, D.
|
- Curmi, P.M.G.
- Feller, G.
- D'Amico, S.
|
- Gerday, C.
- Uversky, V.N.
- Cavicchioli, R.
|
| Abstract |
The cold-adapted α-amylase from Pseudoalteromonas haloplanktis (AHA) is a multidomain enzyme capable of reversible unfolding. Cold-adapted proteins, including AHA, have been predicted to be structurally flexible and conformationally unstable as a consequence of a high lysine-to-arginine ratio. In order to examine the role of low arginine content in structural flexibility of AHA, the amino groups of lysine were guanidinated to form homo-arginine (hR), and the structure–function–stability properties of the modified enzyme were analyzed by transverse urea gradient-gel electrophoresis. The extent of modification was monitored by MALDI-TOF-MS, and correlated to changes in activity and stability. Modifying lysine to hR produced a conformationally more stable and less active α-amylase. The kcat of the modified enzyme decreased with a concomitant increase in ΔH# and decrease in Km. To interpret the structural basis of the kinetic and thermodynamic properties, the hR residues were modeled in the AHA X-ray structure and compared to the X-ray structure of a thermostable homolog. The experimental properties of the modified AHA were consistent with K106hR forming an intra-Domain B salt bridge to stabilize the active site and decrease the cooperativity of unfolding. Homo-Arg modification also appeared to alter Ca2+ and Cl− binding in the active site. Our results indicate that replacing lysine with hR generates mesophilic-like characteristics in AHA, and provides support for the importance of lysine residues in promoting enzyme cold adaptation. These data were consistent with computational analyses that show that AHA possesses a compositional bias that favors decreased conformational stability and increased flexibility. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
