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Sabo KA, Albekioni E, Caliger D, Coleman NJ, Thornberg E, Avellaneda Matteo D, Komives EA, Silletti S, Sohl CD. Capturing the Dynamic Conformational Changes of Human Isocitrate Dehydrogenase 1 (IDH1) upon Ligand and Metal Binding Using Hydrogen-Deuterium Exchange Mass Spectrometry. Biochemistry 2023; 62:1145-1159. [PMID: 36854124 PMCID: PMC10089636 DOI: 10.1021/acs.biochem.2c00636] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Human isocitrate dehydrogenase 1 (IDH1) is a highly conserved metabolic enzyme that catalyzes the interconversion of isocitrate and α-ketoglutarate. Kinetic and structural studies with IDH1 have revealed evidence of striking conformational changes that occur upon binding of its substrates, isocitrate and NADP+, and its catalytic metal cation. Here, we used hydrogen-deuterium exchange mass spectrometry (HDX-MS) to build a comprehensive map of the dynamic conformational changes experienced by IDH1 upon ligand binding. IDH1 proved well-suited for HDX-MS analysis, allowing us to capture profound changes in solvent accessibility at substrate binding sites and at a known regulatory region, as well as at more distant local subdomains that appear to support closure of this protein into its active conformation. HDX-MS analysis suggested that IDH1 is primarily purified with NADP(H) bound in the absence of its metal cation. Subsequent metal cation binding, even in the absence of isocitrate, was critical for driving large conformational changes. WT IDH1 folded into its fully closed conformation only when the full complement of substrates and metal was present. Finally, we show evidence supporting a previously hypothesized partially open conformation that forms prior to the catalytically active state, and we propose this conformation is driven by isocitrate binding in the absence of metal.
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Affiliation(s)
- Kaitlyn A Sabo
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Elene Albekioni
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Danielle Caliger
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Nalani J Coleman
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Ella Thornberg
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Diego Avellaneda Matteo
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
| | - Elizabeth A Komives
- University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, California 92093, United States
| | - Steve Silletti
- University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, California 92093, United States
| | - Christal D Sohl
- San Diego State University, Department of Chemistry and Biochemistry, San Diego, California 92182, United States
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Gramlich M, Maier S, Kaiser PD, Traenkle B, Wagner TR, Voglmeir J, Stoll D, Rothbauer U, Zeck A. A Novel PNGase Rc for Improved Protein N-Deglycosylation in Bioanalytics and Hydrogen-Deuterium Exchange Coupled With Mass Spectrometry Epitope Mapping under Challenging Conditions. Anal Chem 2022; 94:9863-9871. [PMID: 35749695 DOI: 10.1021/acs.analchem.2c01748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
N-linked glycosylation is a ubiquitous posttranslational modification of proteins. While it plays an important role in the biological function of proteins, it often poses a major challenge for their analytical characterization. Currently available peptide N-glycanases (PNGases) are often inefficient at deglycosylating proteins due to sterically inaccessible N-glycosylation sites. This usually leads to poor sequence coverage in bottom-up analysis using liquid chromatography with tandem mass spectrometry and makes it impossible to obtain an intact mass signal in top-down MS analysis. In addition, most PNGases operate optimally only in the neutral to slightly acidic pH range and are severely compromised in the presence of reducing and denaturing substances, which limits their use for advanced bioanalysis based on hydrogen-deuterium exchange in combination with mass spectrometry (HDX-MS). Here, we present a novel peptide N-glycanase from Rudaea cellulosilytica (PNGase Rc) for which we demonstrate broad substrate specificity for N-glycan hydrolysis from multiply occupied and natively folded proteins. Our results show that PNGase Rc is functional even under challenging, HDX quenching conditions (pH 2.5, 0 °C) and in the presence of 0.4 M tris(2-carboxyethyl)phosphine, 4 M urea, and 1 M guanidinium chloride. Most importantly, we successfully applied the PNGase Rc in an HDX-MS workflow to determine the epitope of a nanobody targeting the extracellular domain of human signal-regulating protein alpha (SIRPα).
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Affiliation(s)
- Marius Gramlich
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany
| | - Sandra Maier
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany
| | - Philipp D Kaiser
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany
| | - Bjoern Traenkle
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany
| | - Teresa R Wagner
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany.,Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Josef Voglmeir
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Dieter Stoll
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany.,Department of Life Sciences, University of Applied Sciences Albstadt-Sigmaringen, Sigmaringen 72488, Germany
| | - Ulrich Rothbauer
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany.,Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Anne Zeck
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen 72770, Germany
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