http://www.cnr.it/ontology/cnr/individuo/prodotto/ID173868

Tryptophan phosphorescence studies of the D-galactose/D-glucose-binding protein from Escherichia coli provide a molecular portrait with structural and dynamics features of the protein (Articolo in rivista)

Type

Prodotto della ricerca (Classe)
Articolo in rivista (Classe)

Label

Tryptophan phosphorescence studies of the D-galactose/D-glucose-binding protein from Escherichia coli provide a molecular portrait with structural and dynamics features of the protein (Articolo in rivista) (literal)

Anno

2007-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1021/pr060650n (literal)

Alternative label

D'Auria S.; Varriale A.; Gonnelli M.; Saviano M.; Staiano M.; Rossi M.; Strambini G.B. (2007)
Tryptophan phosphorescence studies of the D-galactose/D-glucose-binding protein from Escherichia coli provide a molecular portrait with structural and dynamics features of the protein
in Journal of proteome research (Print); ACS, American chemical society, Washington, DC (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

D'Auria S.; Varriale A.; Gonnelli M.; Saviano M.; Staiano M.; Rossi M.; Strambini G.B. (literal)

Pagina inizio

1306 (literal)

Pagina fine

1312 (literal)

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6 (literal)

Rivista

Journal of proteome research (Rivista)

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4 (literal)

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Pubblicazione su rivista internazionale (literal)

Note

ISI Web of Science (WOS) (literal)

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Istituto di Biochimica delle Proteine, CNR, Via Pietro Castellino, 111 80131 Naples, Italy; Istituto di Biofisica, CNR Via Moruzzi 1, 56124 Pisa, Italy; Istituto di Biostruttura e Bioimmagini, CNR, Napoli, Italy (literal)

Titolo

Tryptophan phosphorescence studies of the D-galactose/D-glucose-binding protein from Escherichia coli provide a molecular portrait with structural and dynamics features of the protein (literal)

Abstract

The D-galactose/D-glucose-binding protein (GGBP) from E. coli serves as an initial component for both chemotaxis toward glucose and high-affinity active transport of the sugar. In this work, we have used phosphorescence spectroscopy to investigate the effects of glucose and calcium on the dynamics and stability of GGBP. We found that GGBP exhibits a phosphorescence spectrum composed of two energetically distinct 0,0-vibrational bands centered at 404.43 and 409.61 nm; the large energy separation between them indicates two classes of chromophores making distinct dipolar interactions with their surrounding. Interestingly, the high-energy spectral component (404.43 nm) is one of the bluest spectra reported to date in proteins. Considering the ground state dipole direction, low-energy configurations for the indole side chain in proteins leading to blue-shifted spectra can arise from negative charges in proximity to the imidazole-ring nitrogen and/or positive charges near C4-C5 of the benzene ring. Among the five tryptophan residues of GGBP, Trp-284, located at the N-terminal domain of the protein, and Trp-183, located in the protein hinge region, make strong attractive charge interactions with surrounding side chains. Regarding Trp-284, the indole ring nitrogen is in contact with the negative charge of the Asp-267, whereas Trp-183 is next to the Glu-149 residue. In the latter, the ground state energy is further lowered by the proximity of the Arg-158 to the negative end (near C6) of the indole dipole. Regarding the red spectral component (409.61 nm), it is more intense than the blue component, presumably because more residues contribute to it. lambda 0,0 is typical of environments that are weakly polar or characterized by charges positioned near 90 degrees from the ground state dipole direction (the case of W195 and W127). The binding of glucose modifies the phosphorescence lifetime values as well as the spectrum of GGBP, shifting the blue band 0.54 nm to the blue and the red band 1 nm to the red. Finally, the removal of the calcium from GGBP structure causes variations in lifetime values and spectral shifts similar to those induced by glucose binding to the native protein. Aided by a detailed inspection of the three-dimensional structure of GGBP, these results contribute to a better understanding of the structure/function relationship of this protein. (literal)

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