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Full-Text Articles in Physical Sciences and Mathematics
Changes In Enzyme Structural Dynamics Studied By Hydrogen Exchange-Mass Spectrometry: Ligand Binding Effects Or Catalytically Relevant Motions?, Courtney S Fast, Siavash Vahidi, Lars Konermann
Changes In Enzyme Structural Dynamics Studied By Hydrogen Exchange-Mass Spectrometry: Ligand Binding Effects Or Catalytically Relevant Motions?, Courtney S Fast, Siavash Vahidi, Lars Konermann
Chemistry Publications
It is believed that enzyme catalysis is facilitated by conformational dynamics of the protein scaffold that surrounds the active site, yet the exact nature of catalytically relevant protein motions remains largely unknown. Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) reports on backbone H-bond fluctuations. HDX/MS thus represents a promising avenue for probing the relationship between enzyme dynamics and catalysis. A seemingly straightforward strategy for such studies involves comparative measurements during substrate turnover and in the resting state. We examined the feasibility of this approach using rabbit muscle pyruvate kinase (rM1-PK) which catalyzes the conversion of phosphoenolpyruvate and Mg-ADP to pyruvate and …
Cytochrome C As A Peroxidase: Activation Of The Precatalytic Native State By H, Victor Yin, Gary S Shaw, Lars Konermann
Cytochrome C As A Peroxidase: Activation Of The Precatalytic Native State By H, Victor Yin, Gary S Shaw, Lars Konermann
Chemistry Publications
In addition to serving as respiratory electron shuttle, ferri-cytochrome c (cyt c) acts as a peroxidase; i.e., it catalyzes the oxidation of organic substrates by H2O2. This peroxidase function plays a key role during apoptosis. Typical peroxidases have a five-coordinate heme with a vacant distal coordination site that permits the iron center to interact with H2O2. In contrast, native cyt c is six-coordinate, as the distal coordination site is occupied by Met80. It thus seems counterintuitive that native cyt c would exhibit peroxidase activity. The current work scrutinizes the origin of this …
Calcium-Mediated Control Of S100 Proteins: Allosteric Communication Via An Agitator/Signal Blocking Mechanism., Yiming Xiao, Gary S Shaw, Lars Konermann
Calcium-Mediated Control Of S100 Proteins: Allosteric Communication Via An Agitator/Signal Blocking Mechanism., Yiming Xiao, Gary S Shaw, Lars Konermann
Chemistry Publications
Allosteric proteins possess dynamically coupled residues for the propagation of input signals to distant target binding sites. The input signals usually correspond to "effector is present" or "effector is not present". Many aspects of allosteric regulation remain incompletely understood. This work focused on S100A11, a dimeric EF-hand protein with two hydrophobic target binding sites. An annexin peptide (Ax) served as the target. Target binding is allosterically controlled by Ca2+ over a distance of ∼26 Å. Ca2+ promotes formation of a [Ca4 S100 Ax2] complex, where the Ax peptides are accommodated between helices III/IV and III'/IV'. …