Characterization of the ubiquitin-domain containing protein Nmag_2608of the archaeon Nab. magadii.

SOLCHAGA JI; D VILLAMONTE ; MV ORDÓÑEZ; D NERCESSIAN

Mar del Plata

Congreso; - SAIB - 51 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2015

SAIB

Although Ubiquitinis restricted to eukaryotes, ubiquitin-like proteins/domains (Ubl/Uld) arefound in all domains of life. They donot share high sequence identity but display the β-grasp fold and often exhibit the C-terminal di-glycinemotif characteristic of Ubiquitin.Nmag_2608 is anubiquitin-like domain (Uld) protein from the haloalkaliphilic archaeon Natrialbamagadii expressed and secreted to the extracellular medium at earlystationary phase. Its Uld, P400, has been previously identified andcharacterized. The aim of this work was evaluating the physiological role ofNmag_2608 and the importance of P400 in this role. For this, P400 washeterologously expressed in E. coliand purified. Given Nmag_2608 localization, a possible role in nutrient uptakewas explored by evaluating the interaction of P400 with different aminoacids atseveral ratios (1:10;1:50). Different peaks and their UV spectrum obtained fromHPLC analysis of the mixtures were compared with that of sample containing onlyp400r or amino acids. Differential peaks were collected and interactionconfirmed by Western blot assays with Anti-P400. Results showed that P400interacts only with tryptophan. HPLC assay showed a new pattern appears withcharacteristic absorbance spectrum which corresponds with interactingP400r-Trp. This interaction could be necessary for the activity of P400 in theextracellular medium.