Nanobodies are single domain antibodies (sdAbs) derived from camelid heavy chain
antibody[1,2]. They are characterized by their small size (~12-16 kDa), high stability,
specificity and solubility[1-4]. Therefore, sdAbs are considered non-immunogenics due to their high similarity with variable domain sequences of heavy chains of human antibodies[5]. In this work, the expression of a nanobody (126 amino acids) from camelid – that recognizes the Fc region of IgG in rats, mice and humans – was studied under different conditions (temperature, time, culture media, strain) for determining the better conditions of expression. For the NMR analysis, the cell growth was performed in M9 medium, enriched with 13 C and 15 N, overnight, at 37ºC and using Escherichia coli host and transformation using a pet-25b vector. The protein was purified by immobilized metal affinity chromatography followed by a size-exclusion chromatography. The thermal stability of the sdAb-mrh-IgG was measured using circular dichroism. NMR spectra were acquired for the assignment of the backbone using a 600 MHz spectrometer (Bruker Avance III) with a 5 mm probe at a controlled temperature of 298K.