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Updated: Aug 12, 2026
07:38
Measuring In Vitro ATPase Activity for Enzymatic Characterization
Published on: August 23, 2016
Real-time Structural Tracking of Slow P-type ATPase Dynamics
K Magkakis1, F Sabzian-Molaei1, F Orädd1
1Department of Chemistry, Umeå University, Umeå, Sweden.
The Journal of Membrane Biology
|August 11, 2026
Summary
Extended time-resolved X-ray solution scattering (TR-XSS) now probes slow protein dynamics up to seconds. This method reveals multi-step conformational changes in enzymes like P-type ATPases.
Area of Science:
- Structural Biology
- Biophysics
- Biochemistry
Background:
- Time-resolved X-ray solution scattering (TR-XSS) is crucial for studying protein dynamics.
- Current TR-XSS methods are limited to millisecond timescales, hindering the study of slow enzymatic systems like P-type ATPases.
Purpose of the Study:
- To extend the temporal range of TR-XSS to sub-second and second timescales.
- To enable the study of slow conformational dynamics in enzymes, particularly P-type ATPases.
Main Methods:
- Developed a strategy using sequentially positioned, radiation damage-free acquisition windows for TR-XSS.
- Applied the extended-time TR-XSS method at the CoSAXS beamline, MAX IV Laboratory.
- Utilized adenylate kinase (AdK) as a benchmark and studied the prokaryotic P-type ATPase LMCA1.
Main Results:
- Observed a single conformational transition with signal decay in AdK.
- Resolved sequential conformational transitions in LMCA1 with timescales of 140 ms and 660 ms.
- Demonstrated the ability to track intermediate dynamics in slow transport cycles.
Conclusions:
- Extended-time TR-XSS successfully resolves multi-step reaction pathways in slow membrane proteins.
- The approach significantly broadens the accessible timescale for TR-XSS.
- Established a general framework for studying slow conformational dynamics in P-type ATPases and similar systems.
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