Characterization of the Ubiquitin-domain containing protein Nmag_2608 of the archaeon Natrialba magadii

SOLCHAGA, JI; ORDOÑEZ, M. V.; VILLAMONTE, DANIELA; NERCESSIAN, D.

Mar del Plata

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Although Ubiquitin is restricted to eukaryotes, ubiquitin-like proteins/domains (Ubl/Uld) are found in all domains of life. They do not share high sequence identity but display theβ-grasp fold and often exhibit the C-terminal di-glycine motif characteristic of ubiquitin. Nmag_2608 is an ubiquitin-like domain (Uld) protein from the haloalkaliphilic archaeon Natrialba magadii expressed and secreted to the extracellular medium at early stationary phase. Its Uld, P400, has been previously identified and characterized. The aim of this work was evaluating the physiological role of Nmag_2608 and the importance of P400 in this role. For this, P400 was heterologously expressed in E. coli and purified. Given Nmag_2608 localization, a possible role in nutrient uptake was explored by evaluating the interaction of P400 with different aminoacids at several ratios (1:10;1:50). Different peaks and their UV spectrum obtained from HPLC analysis of the mixtures were compared with that of sample containing only P400r or amino acids. Differential peaks were collected and interaction confirmed by Western blot assays with Anti-P400. Results showed that P400interacts only with tryptophan. HPLC assay showed a new pattern appears with characteristic absorbance spectrum which corresponds with interacting P400r-Trp. This interaction could be necessary for the activity of P400 in the extracellular medium.