scholarly journals Hydrogen Exchange-Mass Spectrometry Analysis of β-Amyloid Peptide Structure†

Biochemistry ◽  
2003 ◽  
Vol 42 (31) ◽  
pp. 9507-9514 ◽  
Author(s):  
Steven S.-S. Wang ◽  
Scott A. Tobler ◽  
Theresa A. Good ◽  
Erik J. Fernandez
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Exchange ◽  
Amyloid Peptide ◽  
Mass Spectrometry Analysis ◽  
Peptide Structure ◽  
Spectrometry Analysis ◽  
Exchange Mass Spectrometry ◽  
Hydrogen Exchange Mass Spectrometry ◽  
Β Amyloid ◽  
Β Amyloid Peptide

scholarly journals Hydrogen exchange reveals Hsp104 architecture, structural dynamics, and energetics in physiological solution

2019 ◽  
Vol 116 (15) ◽  
pp. 7333-7342 ◽  
Author(s):  
Xiang Ye ◽  
Jiabei Lin ◽  
Leland Mayne ◽  
James Shorter ◽  
S. Walter Englander
Keyword(s):  
Hydrogen Exchange ◽  
Atp Hydrolysis ◽  
Physiological Solution ◽  
Mass Spectrometry Analysis ◽  
Structural Element ◽  
Spectrometry Analysis ◽  
Exchange Mass Spectrometry ◽  
Substrate Protein ◽  
Central Pore ◽  
The One

Hsp104 is a large AAA+ molecular machine that can rescue proteins trapped in amorphous aggregates and stable amyloids by drawing substrate protein into its central pore. Recent cryo-EM studies image Hsp104 at high resolution. We used hydrogen exchange mass spectrometry analysis (HX MS) to resolve and characterize all of the functionally active and inactive elements of Hsp104, many not accessible to cryo-EM. At a global level, HX MS confirms the one noncanonical interprotomer interface in the Hsp104 hexamer as a marker for the spiraled conformation revealed by cryo-EM and measures its fast conformational cycling under ATP hydrolysis. Other findings enable reinterpretation of the apparent variability of the regulatory middle domain. With respect to detailed mechanism, HX MS determines the response of each Hsp104 structural element to the different bound adenosine nucleotides (ADP, ATP, AMPPNP, and ATPγS). They are distinguished most sensitively by the two Walker A nucleotide-binding segments. Binding of the ATP analog, ATPγS, tightly restructures the Walker A segments and drives the global open-to-closed/extended transition. The global transition carries part of the ATP/ATPγS-binding energy to the somewhat distant central pore. The pore constricts and the tyrosine and other pore-related loops become more tightly structured, which seems to reflect the energy-requiring directional pull that translocates the substrate protein. ATP hydrolysis to ADP allows Hsp104 to relax back to its lowest energy open state ready to restart the cycle.

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