Id |
Subject |
Object |
Predicate |
Lexical cue |
T1 |
0-149 |
Sentence |
denotes |
Catalysis of GTP hydrolysis by small GTPases at atomic detail by integration of X-ray crystallography, experimental, and theoretical IR spectroscopy. |
T2 |
150-196 |
Sentence |
denotes |
Small GTPases regulate key processes in cells. |
T3 |
197-278 |
Sentence |
denotes |
Malfunction of their GTPase reaction by mutations is involved in severe diseases. |
T4 |
279-362 |
Sentence |
denotes |
Here, we compare the GTPase reaction of the slower hydrolyzing GTPase Ran with Ras. |
T5 |
363-590 |
Sentence |
denotes |
By combination of time-resolved FTIR difference spectroscopy and QM/MM simulations we elucidate that the Mg(2+) coordination by the phosphate groups, which varies largely among the x-ray structures, is the same for Ran and Ras. |
T6 |
591-757 |
Sentence |
denotes |
A new x-ray structure of a Ran·RanBD1 complex with improved resolution confirmed this finding and revealed a general problem with the refinement of Mg(2+) in GTPases. |
T7 |
758-844 |
Sentence |
denotes |
The Mg(2+) coordination is not responsible for the much slower GTPase reaction of Ran. |
T8 |
845-1041 |
Sentence |
denotes |
Instead, the location of the Tyr-39 side chain of Ran between the γ-phosphate and Gln-69 prevents the optimal positioning of the attacking water molecule by the Gln-69 relative to the γ-phosphate. |
T9 |
1042-1100 |
Sentence |
denotes |
This is confirmed in the RanY39A·RanBD1 crystal structure. |
T10 |
1101-1218 |
Sentence |
denotes |
The QM/MM simulations provide IR spectra of the catalytic center, which agree very nicely with the experimental ones. |
T11 |
1219-1305 |
Sentence |
denotes |
The combination of both methods can correlate spectra with structure at atomic detail. |
T12 |
1306-1480 |
Sentence |
denotes |
For example the FTIR difference spectra of RasA18T and RanT25A mutants show that spectral differences are mainly due to the hydrogen bond of Thr-25 to the α-phosphate in Ran. |
T13 |
1481-1712 |
Sentence |
denotes |
By integration of x-ray structure analysis, experimental, and theoretical IR spectroscopy the catalytic center of the x-ray structural models are further refined to sub-Å resolution, allowing an improved understanding of catalysis. |