Mineral Surfaces as Agents of Environmental Proteolysis: Mechanisms and Controls
| Autor: | Rosalie K. Chu, Samuel O. Purvine, Christopher James Burgess, Markus Kleber, David D. Myrold, Therese R. W. Clauss, Eric D. Walter, Nancy M. Washton, Stephany S. Chacon, Patrick N. Reardon |
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| Rok vydání: | 2019 |
| Předmět: |
Birnessite
Proteolysis Peptide 010501 environmental sciences Tandem mass spectrometry Cleavage (embryo) 01 natural sciences Redox Soil Hydrolysis MD Multidisciplinary medicine Environmental Chemistry Kaolinite Kaolin 0105 earth and related environmental sciences chemistry.chemical_classification Minerals medicine.diagnostic_test General Chemistry chemistry Biophysics Oxidation-Reduction Environmental Sciences |
| Zdroj: | Chacon, Stephany S; Reardon, Patrick N; Burgess, Christopher J; Purvine, Samuel; Chu, Rosalie K; Clauss, Therese R; et al.(2019). Mineral Surfaces as Agents of Environmental Proteolysis: Mechanisms and Controls. Environmental Science & Technology, 53(6), 3018-3026. doi: 10.1021/acs.est.8b05583. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/0dp5386b Environmental science & technology, vol 53, iss 6 |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/acs.est.8b05583 |
| Popis: | We investigated the extent to which contact with mineral surfaces affected the molecular integrity of a model protein, with an emphasis on identifying the mechanisms (hydrolysis, oxidation) and conditions leading to protein alteration. To this end, we studied the ability of four mineral surface archetypes (negatively charged, positively charged, neutral, redox-active) to abiotically fragment a well-characterized protein (GB1) as a function of pH and contact time. GB1 was exposed to the soil minerals montmorillonite, goethite, kaolinite, and birnessite at pH 5 and pH 7 for 1, 8, 24, and 168 h and the supernatant was screened for peptide fragments using Tandem Mass Spectrometry. To distinguish between products of oxidative and hydrolytic cleavage, we combined results from the SEQUEST algorithm, which identifies protein fragments that were cleaved hydrolytically, with the output of a deconvolution algorithm (DECON-Routine) designed to identify oxidation fragments. All four minerals were able to induce protein cleavage. Manganese oxide was effective at both hydrolytic and oxidative cleavage. The fact that phyllosilicates-which are not redox active-induced oxidative cleavage indicates that surfaces acted as catalysts and not as reactants. Our results extend previous observations of proteolytic capabilities in soil minerals to the groups of phyllosilicates and Fe-oxides. We identified structural regions of the protein with particularly high susceptibility to cleavage (loops and β strands) as well as regions that were entirely unaffected (α helix). |
| Databáze: | OpenAIRE |
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