References of "D'Amico, Salvino"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailA peptide mimicking the C-terminal part of the reactive center loop induces the transition to the latent form of Plasminogen Activator Inhibitor Type-1
D'Amico, Salvino ULg; Martial, Joseph ULg; Struman, Ingrid ULg

in FEBS Letters (2012), 586

Plasminogen Activator Inhibitor-1 (PAI-1) is the primary inhibitor of plasminogen activators (uPA and tPA) and thus plays a central role in fibrinolysis. The spontaneous insertion of its Reactive Centre ... [more ▼]

Plasminogen Activator Inhibitor-1 (PAI-1) is the primary inhibitor of plasminogen activators (uPA and tPA) and thus plays a central role in fibrinolysis. The spontaneous insertion of its Reactive Centre Loop (RCL) into beta-sheet A is responsible for its irreversible conversion into the inactive latent form. In this study, we used two peptides mimicking residues P14-P9 and P8-P3 of the RCL so as to understand this dynamic process. We show that both peptides inhibit the formation of PAI 1/uPA and PAI-1/tPA complexes via two different mechanisms. Targeting the N-terminal part of the loop induces the cleavage of PAI-1 by the proteases uPA/tPA while targeting its C-terminal part greatly favors the irreversible formation of latent PAI-1. [less ▲]

Detailed reference viewed: 56 (37 ULg)
Full Text
See detailActivity-Flexibility and Stability Relationships as revealed by multiple mutants of a psychrophilic alpha-Amylase
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2011, May 23)

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have ... [more ▼]

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium Pseudoalteromonas haloplanktis. Two stabilized multiple-mutants (Mut5 and Mut5CC) have been constructed. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic homolog from pig pancreas, PPA. The three enzymes AHA, Mut5 and Mut5CC have been analyzed by differential scanning calorimetry, thermal and chemical denaturation. The flexibility has been studied by acrylamide-induced fluorescence quenching. In order to investigate the kinetic origin of the gain in stability, the kinetics of unfolding and refolding in GdmCl have been monitored at 15°C. The newly introduced weak interactions stabilized the mutants, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. In addition, the two multiple-mutants exhibit an increased optimum temperature for activity. The first results of kinetic studies show a similar refolding phase but differences between the three amylases in the unfolding phase. These results unambiguously support the capital role of weak interactions in the balance between activity, flexibility and stability and provide a better knowledge of the adaptation of enzymes to cold temperatures. [less ▲]

Detailed reference viewed: 30 (7 ULg)
Full Text
Peer Reviewed
See detailStepwise adaptations to low temperature as revealed by multiple mutants of a psychrophilic alpha-amylase from an Antarctic bacterium
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Barumandzadeh, Roya et al

in Journal of Biological Chemistry (2011), 286(44), 3834838355

Detailed reference viewed: 31 (9 ULg)
Full Text
See detailCold adaptation of proteins: a biophysical study of a psychrophilic alpha-amylase and its stabilized mutants
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2010, September 28)

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold ... [more ▼]

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold environments. According to the hypothesis developed in our laboratory, the adaptation to cold temperature involves relationships between activity, flexibility and stability. Even if activity and stability are not physically linked in proteins 1, the consensus for the adaptive strategy is to take advantage of the lack of selective pressure for stable proteins to lose stability, therefore increasing the flexibility or mobility of the enzyme at low temperatures that restrict molecular motions. 2 Working on alpha-amylase, we have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis. We have built two multiple-mutants (Mut5 and Mut5CC) of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium, Pseudoalteromonas haloplanktis. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic chloride-dependant homolog from pig pancreas, PPA. The study of selected single mutations prompt us to construct two multiple-mutants, Mut5 and Mut5CC, carrying 5 and 6 additional weak interactions found in PPA, that showed an increased stability and a lower activity at 25 °C.3 We have compared AHA, Mut5 and Mut5CC with additional methods like differential scanning calorimetry, thermal and chemical unfolding in order to determine the gain in stability. We also studied the flexibility or breathing of the enzymes by acrylamide-induced fluorescence quenching and we determined the optimum activity temperature for the three amylases. In order to investigate the kinetic origin of the gain in stability 4 for the two multiple-mutants, we studied in a first step the kinetic unfolding and refolding by GdmCl of the three amylases by manual methods following fluorescence signal at 15°C. The newly introduced weak interactions stabilized the proteins, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. In addition, the two multiple-mutants exhibit a different optimum activity temperature than AHA. The first result in manual kinetic studies seems to show a similar refolding phase but a difference between the three amylases in the unfolding phase. This is in correlation with results of Dieter, P et al 4. These results and those of the previous work 3, unambiguously support the capital role of weak interactions in the balance between activity, flexibility and stability and provide a better knowledge of the adaptation of enzymes to cold temperatures. [less ▲]

Detailed reference viewed: 62 (5 ULg)
See detailInteractions between Prolactin/Growth Hormone-Derived Peptides and PAI-1
D'Amico, Salvino ULg

Scientific conference (2010)

Detailed reference viewed: 5 (2 ULg)
Full Text
See detailTemperature Adaptation of Proteins: Stability, Folding and Flexibility in Mesophilic-like Engineered Alpha-Amylases
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2009, July 02)

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold ... [more ▼]

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold environments. According to the hypothesis developed in our laboratory, the adaptation to cold temperature involves relationships between activity, flexibility and stability. Even if activity and stability are not physically linked in proteins 1, the consensus for the adaptive strategy is to take advantage of the lack of selective pressure for stable proteins to lose stability, therefore increasing the flexibility or mobility of the enzyme at low temperatures that restrict molecular motions. 2 Working on alpha-amylase, we have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis. We have built two multiple-mutants (Mut5 and Mut5CC) of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium, Pseudoalteromonas haloplanktis. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic chloride-dependant homolog from pig pancreas, PPA. The study of selected single mutations prompt us to construct two multiple-mutants, Mut5 and Mut5CC, carrying 5 and 6 additional weak interactions found in PPA, that showed an increased stability and a lower activity at 25 °C.3 We have compared AHA, Mut5 and Mut5CC with additional methods like differential scanning calorimetry, thermal and chemical unfolding and circular dichroism in order to determine the gain in stability. We also studied the flexibility or breathing of the enzymes by acrylamide-induced fluorescence quenching. The newly introduced weak interactions stabilized the proteins, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. These results and those of the previous work 3, unambiguously support the capital role of weak interactions in the balance between activity, flexibility and stability and provide a better knowledge of the adaptation of enzymes to cold temperatures. [less ▲]

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailInsights into bacterial cellulose biosynthesis by functional metagenomics on Antarctic soil samples.
Berlemont, Renaud ULg; Delsaute, Maud ULg; Pipers, Delphine ULg et al

in ISME Journal (The) (2009), 3(9), 1070-1081

In this study, the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is ... [more ▼]

In this study, the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family 5 of the glycosyl hydrolase (GH5) protein from Pseudomonas stutzeri (Pst_2494) and does not possess a carbohydrate-binding domain. The protein was produced and purified to homogeneity. RBcel1 displayed an endoglucanase activity, producing cellobiose and cellotriose, using carboxymethyl cellulose as a substrate. Moreover, the study of pH and the thermal dependence of the hydrolytic activity shows that RBcel1 was active from pH 6 to pH 9 and remained significantly active when temperature decreased (18% of activity at 10 degrees C). It is interesting that RBcel1 was able to synthetize non-reticulated cellulose using cellobiose as a substrate. Moreover, by a combination of bioinformatics and enzyme analysis, the physiological relevance of the RBcel1 protein and its mesophilic homologous Pst_2494 protein from P. stutzeri, A1501, was established as the key enzymes involved in the production of cellulose by bacteria. In addition, RBcel1 and Pst_2494 are the two primary enzymes belonging to the GH5 family involved in this process.The ISME Journal advance online publication, 21 May 2009; doi:10.1038/ismej.2009.48. [less ▲]

Detailed reference viewed: 90 (36 ULg)
Full Text
Peer Reviewed
See detailA nondetergent sulfobetaine improves protein unfolding reversibility in microcalorimetric studies
D'Amico, Salvino ULg; Feller, Georges ULg

in Analytical Biochemistry (2009), 385(2), 389-91

A nondetergent sulfobetaine (NDSB) was found to improve unfolding reversibility of several proteins by inhibiting heat-induced aggregation. As a consequence, DeltaH(cal)/DeltaH(vH) ratios were also ... [more ▼]

A nondetergent sulfobetaine (NDSB) was found to improve unfolding reversibility of several proteins by inhibiting heat-induced aggregation. As a consequence, DeltaH(cal)/DeltaH(vH) ratios were also improved to values close to 1 for a two-state unfolding. NDSB is effective in a wide range of pH values and especially at acidic pH generally used to calculate DeltaC(p) values by the Kirchhoff relation. The sulfobetaine also allows recording protein refolding by protecting the heat-induced unfolded state against aggregation. [less ▲]

Detailed reference viewed: 18 (4 ULg)
Full Text
Peer Reviewed
See detailSelection of a cold-adapted bacterium for bioremediation of wastewater at low temperatures
Gratia, E.; Weekers, F.; Margesin, R. et al

in Extremophiles : Life Under Extreme Conditions (2009), 13(5), 763-8

Amongst more than 1000 isolates collected in various cold environments, the strain Arthrobacter psychrolactophilus Sp 31.3 has been selected for its ability to grow and to produce exoenzymes at low ... [more ▼]

Amongst more than 1000 isolates collected in various cold environments, the strain Arthrobacter psychrolactophilus Sp 31.3 has been selected for its ability to grow and to produce exoenzymes at low temperatures, its inability to grow at 37 degrees C, its non-halophilic character and its growth versatility on various media. This non-pathogenic strain displays a strong resistance to desiccation and storage at room temperature and is suitable for the production of freeze-dried bacterial starters. When grown in a synthetic wastewater at 10 degrees C, the strain induces a complete clarification of the turbid medium and efficiently hydrolyses proteins, starch and lipids in the broth. Furthermore, this strain has a remarkable capacity to improve the biodegradability of organic compounds in wastewater as indicated by a BOD(5)/COD ratio of 0.7. [less ▲]

Detailed reference viewed: 47 (13 ULg)
Full Text
See detailFundamentals of Cold-Adapted Enzymes
Collins, T.; Roulling, Frédéric ULg; Piette, Florence ULg et al

in Margesin, R.; Schinner, F.; Gerday, Charles (Eds.) et al Psychrophiles: from Biodiversity to Biotechnology (2008)

Detailed reference viewed: 36 (14 ULg)
See detailFundamentals of Cold-Adapted Enzymes
D'Amico, Salvino ULg

Scientific conference (2007)

Detailed reference viewed: 6 (0 ULg)
See detailCold-Adapted Enzymes
Collins, T.; D'Amico, Salvino ULg; Marx, J. C. et al

in Gerday, Charles; Glansdorff, N. (Eds.) Physiology and biochemistry of extremophiles (2007)

Detailed reference viewed: 27 (1 ULg)
Full Text
See detailAdaptation strategies and uses of cold adapted enzymes in biotechnological processes
Gerday, Charles ULg; D'Amico, Salvino ULg; Collins, T. et al

in JAMSTEC ERC (Ed.) Proceedings of the International Symposium on Extremophiles and their Applications 2005 (2007)

Detailed reference viewed: 27 (0 ULg)
Full Text
Peer Reviewed
See detailCold-adapted enzymes from marine antarctic microorganisms
Marx, J. C.; Collins, T.; D'Amico, Salvino ULg et al

in Marine Biotechnology (2007), 9(3, May-Jun), 293-304

The Antarctic marine environment is characterized by challenging conditions for the survival of native microorganisms. Indeed, next to the temperature effect represented by the Arrhenius law, the ... [more ▼]

The Antarctic marine environment is characterized by challenging conditions for the survival of native microorganisms. Indeed, next to the temperature effect represented by the Arrhenius law, the viscosity of the medium, which is also significantly enhanced by low temperatures, contributes to slow down reaction rates. This review analyses the different challenges and focuses on a key element of life at low temperatures: cold-adapted enzymes. The molecular characteristics of these enzymes are discussed as well as the adaptation strategies which can be inferred from the comparison of their properties and three-dimensional structures with those of their mesophilic counterparts. As these enzymes display a high specific activity at low and moderate temperatures associated with a relatively high thermosensitivity, the interest in these properties is discussed with regard to their current and possible applications in biotechnology. [less ▲]

Detailed reference viewed: 53 (3 ULg)