The transpeptidation activity of γ-glutamyltranspeptidase from Geobacillus thermodenitrificans (GthGT) is 27 negligible and the enzyme is highly thermostable. Here we have examined the effect of concentrated NaCl 28 solutions on structure, stability, dynamics and enzymatic activity of GthGT. The protein exhibited hydrolytic 29 activity over a broad range of NaCl concentrations. Even at 4.0 M NaCl, GthGT retained more than 90% of the 30 initial activity and showed unaltered fluorescence emission, secondary structure and acrylamide quenching 31 on tryptophan fluorescence. Furthermore, at 2.8 M and 4.0 M NaCl the temperature-induced unfolding pro- 32 files are dramatically changed with large (>20 °C) positive shifts in the denaturation temperature. These fea- 33 tures make GthGT an ideal system to be used in industrial processes that require high temperatures and 34 high-salt environments. A general explanation of the NaCl effect by means of a statistical thermodynamic 35 model is also provided, together with an analysis of residue distribution between protein surface and interior 36 in 15 non-redundant families of halophilic and non-halophilic proteins. The results are in line with a compar- 37 ative sequence and structural analysis between halophilic and non-halophilic γ-glutamyltranspeptidases 38 which revealed that a major role in halotolerance should be played by solvent exposed negatively charged 39 residues.

Effect of NaCl on the conformational stability of the thermophilic γ-glutamyltranspeptidase from Geobacillus thermodenitrificans: Implication for globular protein halotolerance / Pica, Andrea; RUSSO KRAUSS, Irene; Castellano, I.; La Cara, F.; Graziano, G; Sica, Filomena; Merlino, Antonello. - In: BIOCHIMICA ET BIOPHYSICA ACTA. - ISSN 0006-3002. - ELETTRONICO. - 1834:(2013), pp. :149-157. [10.1016/j.bbapap.2012.09.014]

Effect of NaCl on the conformational stability of the thermophilic γ-glutamyltranspeptidase from Geobacillus thermodenitrificans: Implication for globular protein halotolerance.

PICA, ANDREA;RUSSO KRAUSS, IRENE;Castellano I.;SICA, FILOMENA;MERLINO, ANTONELLO
2013

Abstract

The transpeptidation activity of γ-glutamyltranspeptidase from Geobacillus thermodenitrificans (GthGT) is 27 negligible and the enzyme is highly thermostable. Here we have examined the effect of concentrated NaCl 28 solutions on structure, stability, dynamics and enzymatic activity of GthGT. The protein exhibited hydrolytic 29 activity over a broad range of NaCl concentrations. Even at 4.0 M NaCl, GthGT retained more than 90% of the 30 initial activity and showed unaltered fluorescence emission, secondary structure and acrylamide quenching 31 on tryptophan fluorescence. Furthermore, at 2.8 M and 4.0 M NaCl the temperature-induced unfolding pro- 32 files are dramatically changed with large (>20 °C) positive shifts in the denaturation temperature. These fea- 33 tures make GthGT an ideal system to be used in industrial processes that require high temperatures and 34 high-salt environments. A general explanation of the NaCl effect by means of a statistical thermodynamic 35 model is also provided, together with an analysis of residue distribution between protein surface and interior 36 in 15 non-redundant families of halophilic and non-halophilic proteins. The results are in line with a compar- 37 ative sequence and structural analysis between halophilic and non-halophilic γ-glutamyltranspeptidases 38 which revealed that a major role in halotolerance should be played by solvent exposed negatively charged 39 residues.
2013
Effect of NaCl on the conformational stability of the thermophilic γ-glutamyltranspeptidase from Geobacillus thermodenitrificans: Implication for globular protein halotolerance / Pica, Andrea; RUSSO KRAUSS, Irene; Castellano, I.; La Cara, F.; Graziano, G; Sica, Filomena; Merlino, Antonello. - In: BIOCHIMICA ET BIOPHYSICA ACTA. - ISSN 0006-3002. - ELETTRONICO. - 1834:(2013), pp. :149-157. [10.1016/j.bbapap.2012.09.014]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/518372
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 20
  • ???jsp.display-item.citation.isi??? 19
social impact