D-trehalose/D-maltose-binding protein from the hyperthermophilic archaeon Thermococcus litoralis: the binding of trehalose and maltose results in different protein conformational states.
In this work, we used fluorescence spectroscopy, molecular dynamics simulation, and Fourier transform infrared spectroscopy for investigating the effect of trehalose binding and maltose binding on the structural properties and the physical parameters of the recombinant D-trehalose/D-maltose binding protein (TMBP) from the hyperthermophilic archaeon Thermococcus litoralis. The binding of the two sugars to TMBP was studied in the temperature range 20 degrees-100 degrees C. The results show that TMBP possesses remarkable temperature stability and its secondary structure does not melt up to 90 degrees C. Although both the secondary structure itself and the sequence of melting events were not significantly affected by the sugar binding, the protein assumes different conformations with different physical properties depending whether maltose or trehalose is bound to the protein. At low and moderate temperatures, TMBP possesses a structure that is highly compact both in the absence and in the presence of two sugars. At about 90 degrees C, the structure of the unliganded TMBP partially relaxes whereas both the TMBP/maltose and the TMBP/trehalose complexes remain in the compact state. In addition, Fourier transform infrared results show that the population of alpha-helices exposed to the solvent was smaller in the absence than in the presence of the two sugars. The spectroscopic results are supported by molecular dynamics simulations. Our data on dynamics and stability of TMBP can contribute to a better understanding of transport-related functions of TMBP and constitute ground for targeted modifications of this protein for potential biotechnological applications.
Faculty of Mathematics and Physics, Institute of Physics, Charles University, Prague, Czech Republic. herman@karlov.mff.cuni.cz
Petr
P
Herman
Maria
M
Staiano
Anna
A
Marabotti
Antonio
A
Varriale
Andrea
A
Scirè
Fabio
F
Tanfani
Jaroslav
J
Vecer
Mose'
M
Rossi
Sabato
S
D'Auria
D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D003198:Computer Simulation; D008320:Maltose / Q000737:chemistry / Q000378:metabolism*; D058619:Maltose-Binding Proteins; D008958:Models, Molecular; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013379:Substrate Specificity; D013696:Temperature; D019712:Thermococcus / Q000737:chemistry* / Q000378:metabolism*; D013997:Time Factors; D014199:Trehalose / Q000737:chemistry / Q000378:metabolism*
D002352:Carrier Proteins; D058619:Maltose-Binding Proteins; D008320:Maltose; D014199:Trehalose