INVESTIGADORES
NERCESSIAN Debora
artículos
Título:
Secondary structure determination by FTIR of an archaeal ubiquitin-like polypeptide from Natrialba magadii.
Autor/es:
ORDÓÑEZ, M.V.; GUILLEN CASAS, J.; NERCESSIAN, D.; VILLALAÍN, J.; CONDE, R.D.
Revista:
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS
Editorial:
SPRINGER
Referencias:
Año: 2011 vol. 40 p. 1101 - 1107
ISSN:
0175-7571
Resumen:
The ubiquitin family of proteins belongs to the β-grasp fold,
characterized by 4-5 β-sheets with a single α-helical middle region.
Ubiquitin-like proteins (Ubls) are low sequence identity structural homologues
to ubiquitin widely spread among both eukaryotes and prokaryotes. We previously
demostrated by bioinformatic analysis that P400, a polypeptide from the
haloalkaliphilic archaeon Natrialba
magadii, has structural homology with both ubiquitin and Ubls. This work
examines the secondary structure of P400 by Fourier Transform Infrarred
spectroscopy (FTIR). After expression in Escherichia
coli, recombinant P400 (rP400) was separated by PAGE and eluted pure from
Zinc-Imidazol reversely stained gels. Then it was lyophilized and rehydrated in
buffer containing 1.5M KCl before both immunochemical and FTIR tests were
performed. It was found that rP400 reacts with anti-ubiquitin antibody after rehydration
in the presence of high salt concentrations. On the other hand, like ubiquitin
and Ubls, the Amide I´ band for rP400 shows 10% more of its sequence involved
in β-sheet structures than in α-helix. These findings suggest that P400 is a
structural homologue of the ubiquitin family proteins.