Back to Search
Start Over
Structural and functional properties of Escherichia coli-derived nucleoplasmin - A comparative study of recombinant and natural proteins
- Source :
- ResearcherID
-
Abstract
- Fourier transform infrared spectroscopy, circular dichroism and prediction techniques have been used to investigate the conformational properties of nucleoplasmin isolated from oocytes and eggs of Xenopus. laevis and overexpressed in Escherichia coli. A simple and fast method allows purification of recombinant nucleoplasmin free of truncated and/or aggregated forms, and therefore provides a suitable sample to carry out the structural and functional comparison between these proteins. The secondary structure of the three proteins estimated from both spectroscopic techniques was very similar, and was found to be 31--33% loops, 27--34% beta structure, 22--26% turns and 9-14% alpha helix. Prediction studies, in good agreement with experimental data, also suggest that beta structure is the major regular conformation, and that loops and turns are the most abundant conformational features within the secondary structure of nucleoplasmin. Furthermore, the spectroscopic characterization of a truncated version of the protein, lacking 80 residues at the C-terminus, and the prediction data indicate that the secondary structure elements of the protein are segregated into two regions. The N-terminal fragment (comprising residues 1--120) which holds all the putative beta strands, and the solvent-exposed C-terminal region, that is suggested to be enriched in turn and loop structures. The phosphate/protein monomer molar ratios, obtained from chemical analysis and mass spectrometry, are 0, 3 and 7--10 for recombinant, oocyte and egg nucleoplasmin, respectively. Phosphorylation does not significantly affect the secondary structure of the protein, but clearly modulates its ability to decondense sperm nuclei and to remove basic proteins from DNA.
- Subjects :
- Nucleoplasmin
Circular dichroism
Molecular Sequence Data
Beta sheet
Biochemistry
Protein Structure, Secondary
law.invention
Turn (biochemistry)
Xenopus laevis
law
Spectroscopy, Fourier Transform Infrared
Escherichia coli
Animals
Amino Acid Sequence
Phosphorylation
education
Nucleoplasmins
Protein secondary structure
Peptide sequence
education.field_of_study
Sequence Homology, Amino Acid
Chemistry
Circular Dichroism
Nuclear Proteins
Phosphoproteins
Chromatin
Recombinant Proteins
Biophysics
Recombinant DNA
Electrophoresis, Polyacrylamide Gel
Alpha helix
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- ResearcherID
- Accession number :
- edsair.doi.dedup.....07915f9ac095134506fb8c1a96d77cfc