Violetta Weinreb, Gabriel Weinreb, Charles W Carter
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引用次数: 1
Abstract
Landscape descriptions provide a framework for identifying functionally significant dynamic linkages in proteins but cannot supply details. Rate measurements of combinatorial mutations can implicate dynamic linkages in catalysis. A major difficulty is filtering dynamic linkages from the vastly more numerous static interactions that stabilize domain folding. The Geobacillus stearothermophilus (TrpRS) D1 switch is such a dynamic packing motif; it links domain movement to catalysis and specificity. We describe Thermofluor and far UV circular dichroism melting curves for all 16 D1 switch variants to determine their higher-order impact on unliganded TrpRS stability. A prominent transition at intermediate temperatures in TrpRS thermal denaturation is molten globule formation. Combinatorial analysis of thermal melting transcends the protein landscape in four significant respects: (i) bioinformatic methods identify dynamic linkages from coordinates of multiple conformational states. (ii) Relative mutant melting temperatures, δTM, are proportional to free energy changes. (iii) Structural analysis of thermal melting implicates unexpected coupling between the D1 switch packing and regions of high local frustration. Those segments develop molten globular characteristics at the point of greatest complementarity to the chemical transition state and are the first TrpRS structures to melt. (iv) Residue F37 stabilizes both native and molten globular states; its higher-order interactions modify the relative intrinsic impacts of mutations to other D1 switch residues from those estimated for single point mutants. The D1 switch is a central component of an escapement mechanism essential to free energy transduction. These conclusions begin to relate the escapement mechanism to differential TrpRS conformational stabilities.
Structural Dynamics-UsCHEMISTRY, PHYSICALPHYSICS, ATOMIC, MOLECU-PHYSICS, ATOMIC, MOLECULAR & CHEMICAL
CiteScore
5.50
自引率
3.60%
发文量
24
审稿时长
16 weeks
期刊介绍:
Structural Dynamics focuses on the recent developments in experimental and theoretical methods and techniques that allow a visualization of the electronic and geometric structural changes in real time of chemical, biological, and condensed-matter systems. The community of scientists and engineers working on structural dynamics in such diverse systems often use similar instrumentation and methods.
The journal welcomes articles dealing with fundamental problems of electronic and structural dynamics that are tackled by new methods, such as:
Time-resolved X-ray and electron diffraction and scattering,
Coherent diffractive imaging,
Time-resolved X-ray spectroscopies (absorption, emission, resonant inelastic scattering, etc.),
Time-resolved electron energy loss spectroscopy (EELS) and electron microscopy,
Time-resolved photoelectron spectroscopies (UPS, XPS, ARPES, etc.),
Multidimensional spectroscopies in the infrared, the visible and the ultraviolet,
Nonlinear spectroscopies in the VUV, the soft and the hard X-ray domains,
Theory and computational methods and algorithms for the analysis and description of structuraldynamics and their associated experimental signals.
These new methods are enabled by new instrumentation, such as:
X-ray free electron lasers, which provide flux, coherence, and time resolution,
New sources of ultrashort electron pulses,
New sources of ultrashort vacuum ultraviolet (VUV) to hard X-ray pulses, such as high-harmonic generation (HHG) sources or plasma-based sources,
New sources of ultrashort infrared and terahertz (THz) radiation,
New detectors for X-rays and electrons,
New sample handling and delivery schemes,
New computational capabilities.