Mechanisms and Consequences of Protein Adsorption on Soil Mineral Surfaces

Quiquampoix, Hervé; Abadie, Josiane; Baron, Marie‐Hélène; Leprince, Franck; Matumoto‐Pintro, Paula Toshimi; Ratcliffe, R. G.; Staunton, Siobhán

doi:10.1021/bk-1995-0602.ch023

Cited by 69 publications

(42 citation statements)

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“…Adsorption would physically separate DNA and the nuclease on the clay surface. This statement is in agreement with the fact that bound enzymes usually exhibit reduced activity (5,11,13,24,29,32). Furthermore, the lower level of protection found with illite compared to kaolinite and montmorillonite could be due to the higher affinity of DNase I for the two other clay minerals as we have observed recently (unpublished results).…”

Section: Discussionsupporting

confidence: 88%

“…For instance, does adsorption physically prevent DNA from being attacked by nucleases? Or is protection related to adsorption of enzymes on clay, which induces conformation alterations leading to a decrease in activity (11,17,24,33,34)? Moreover, how is the remaining clay-adsorbed DNA available for bacterial transformation, and what are the consequences of a partial protection on the transformation efficiency?…”

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confidence: 99%

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Evaluation of Biological and Physical Protection against Nuclease Degradation of Clay-Bound Plasmid DNA

Demanèche

Jocteur-Monrozier

Quiquampoix

et al. 2001

Appl Environ Microbiol

196

139

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In order to determine the mechanisms involved in the persistence of extracellular DNA in soils and to monitor whether bacterial transformation could occur in such an environment, we developed artificial models composed of plasmid DNA adsorbed on clay particles. We determined that clay-bound DNA submitted to an increasing range of nuclease concentrations was physically protected. The protection mechanism was mainly related to the adsorption of the nuclease on the clay mineral. The biological potential of the resulting DNA was monitored by transforming the naturally competent proteobacterium Acinetobacter sp. strain BD413, allowing us to demonstrate that adsorbed DNA was only partially available for transformation. This part of the clay-bound DNA which was available for bacteria, was also accessible to nucleases, while the remaining fraction escaped both transformation and degradation. Finally, transformation efficiency was related to the perpetuation mechanism, with homologous recombination being less sensitive to nucleases than autonomous replication, which requires intact molecules.In the environment, three mechanisms are thought to be involved in gene uptake by bacteria (31), namely, conjugation, transformation, and transduction. Natural bacterial genetic transformation is the mechanism by which a bacterium acquires naked DNA. Such a mechanism is thought to have been involved in gene transfers during evolution and particularly in transfers among unrelated organisms such as plants and bacteria (1,8,21). However, numerous reports indicate that gene transfer events may be very rare in the environment (14,18,33). This could be due to the numerous steps that are required to achieve transformation. DNA released by organisms must persist under adverse conditions such as those encountered in soils. Naked DNA must then encounter competent recipient bacteria. Moreover, the incorporated DNA will only be perpetuated if its nucleotide sequences exhibit sufficient similarity to the recipient genome to allow recombination, unless the sequences possess a replicon which is operational in the new host (14,16,33).Nevertheless, there is a general agreement that natural transformation may occur in complex media such as soils. Indeed, large amounts of naked DNA, which is the preliminary key factor for transformation, can be detected in soils (7,35,40). Moreover, there is much evidence that extracellular DNA can persist for periods of time up to several months or years (8,18,25,27,28,38). Adsorption of DNA on soil components, particularly on clay minerals such as montmorillonite, illite, and kaolinite, is thought to be involved in protection of nucleic acids against nucleases, and could explain the high content of DNA in soils (2, 10, 32). However, soil or microcosm-based experiments have indicated that the adsorption-related protection process has only limited impact (3,17,25,27). In fact, very little is known about the protection mechanism itself, and the influence of parameters such as clay type, the size of DNA or its conformati...

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Section: Discussionsupporting

confidence: 88%

mentioning

confidence: 99%

Evaluation of Biological and Physical Protection against Nuclease Degradation of Clay-Bound Plasmid DNA

Demanèche

Jocteur-Monrozier

Quiquampoix

et al. 2001

Appl Environ Microbiol

196

139

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“…Our analysis also demonstrates that over the entire pD range investigated adsorption of ␣-chymotrypsin on montmorillonite is mainly determined by electrostatic interactions (6,13,16,26,27,29). When the protein and the clay are brought into contact, these interactions result in a dynamic structural transition of the protein which can last up to 1 h. In the 4.5-9 pD range, the unfolding resulting from the adsorption involves about 15-20 peptide units in peripheral ␤-sheets.…”

Section: Discussionmentioning

confidence: 65%

Chymotrypsin Adsorption on Montmorillonite: Enzymatic Activity and Kinetic FTIR Structural Analysis

Baron

Revault

Servagent-Noinville

et al. 1999

Journal of Colloid and Interface Science

Self Cite

111

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Soils have a large solid surface area and high adsorptive capacities. To determine if structural and solvation changes induced by adsorption on clays are related to changes in enzyme activity, alpha-chymotrypsin adsorbed on a phyllosilicate with an electronegative surface (montmorillonite) has been studied by transmission FTIR spectroscopy. A comparison of the pH-dependent structural changes for the solution and adsorbed states probes the electrostatic origin of the adsorption. In the pD range 4.5-10, adsorption only perturbs some peripheral domains of the protein compared to the solution. Secondary structure unfolding affects about 15-20 peptide units. Parts of these domains become hydrated and others entail some self-association. However, the inactivation of the catalytic activity of the adsorbed enzyme in the 5-7 pD range is due less to these structural changes than to steric hindrance when three essential imino/amino functions, located close to the entrance of the catalytic cavity (His-40 and -57 residues and Ala-149 end chain residue), are oriented toward the negatively charged mineral surface. When these functions lose their positive charge, the orientation of the adsorbed enzyme is changed and an activity similar to that in solution at equivalent pH is recovered. This result is of fundamental interest in all fields of research where enzymatic activity is monitored using reversible adsorption procedures. Copyright 1999 Academic Press.

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“…79 Maximum adsorption near the IEP has been shown for many other proteins and surfaces. 98 Because the N-terminal domain is known to be flexibly-disordered and contains a high number of positively-charged amino acids, it may play a significant role in electrostatic attraction to negatively-charged mineral surfaces. 70 The N-terminal domain is lost upon desorption of PrP Sc from clay, 68 and PK-digestion is required to desorb maximal PrP Sc from clay and sandy soils.…”

Section: Routes Of Entry Occurrence and Detection In The Environmentmentioning

confidence: 99%

Prions in the environment

Saunders

Bartelt–Hunt

Bartz

2008

Prion

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Scrapie and CWD are horizontally transmissible, and the environment likely serves as a stable reservoir of infectious prions, facilitating a sustained incidence of CWD in free-ranging cervid populations and complicating efforts to eliminate disease in captive herds. Prions will enter the environment through mortalities and/ or shedding from live hosts. Unfortunately, a sensitive detection method to identify prion contamination in environmental samples has not yet been developed. An environmentally-relevant prion model must be used in experimental studies. Changes in PrP Sc structure upon environmental exposure may be as significant as changes in PrP Sc quantity, since the structure can directly affect infectivity and disease pathology. Prions strongly bind to soil and remain infectious. Conformational changes upon adsorption, competitive sorption and potential for desorption and transport all warrant further investigation. Mitigation of contaminated carcasses or soil might be accomplished with enzyme treatments or composting in lieu of incineration.

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Mechanisms and Consequences of Protein Adsorption on Soil Mineral Surfaces

Cited by 69 publications

References 0 publications

Evaluation of Biological and Physical Protection against Nuclease Degradation of Clay-Bound Plasmid DNA

Evaluation of Biological and Physical Protection against Nuclease Degradation of Clay-Bound Plasmid DNA

Chymotrypsin Adsorption on Montmorillonite: Enzymatic Activity and Kinetic FTIR Structural Analysis

Prions in the environment

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