SUMO is short for Small Ubiquitin-like Modifier, the 100 amino acid sequence, which is necessary for regulation of protein transport and is important for controlling transcription for eukaryotic cells. Sumo tag is most frequently used as N-end fusion sequence in yeast to increase the expression and solubility of the desired recombinant protein.
SUMO proteins are similar to ubiquitin in their folded structure but possess only about 20% homology to the amino acid sequence of ubiquitin. The number of SUMO genes varies among eukaryotes. SUMO proteins are conjugated to substrate proteins in a manner similar to ubiquitin. In addition, SUMO attachment can be removed by SUMO-specific isopeptidases just as UCHs and UBPs remove ubiquitin from substrate proteins.
The preparation of sufficient amounts of high-quality protein samples is the major bottleneck for structural proteomics. In this case, the reversible attachment of small ubiquitin-like modifier (SUMO) protein is a post-translational modification that has been demonstrated to play an important role in various cellular processes.
SUMO proteins are expressed as immature precursors with C-terminal extensions of varying lengths (2–11 amino acids) following a Gly–Gly sequence motif that is the hallmark of the mature C-terminus of SUMO.
SUMO attachment can be removed by SUMO-specific isopeptidases just as UCHs and UBPs remove ubiquitin from substrate proteins. Efficient removal of the SUMO tag by SUMO protease in vitro facilitates the generation of target protein with a native N-terminus.
Guerrero F, et al. (2015) Tandem sumo fusion vectors for improving soluble protein expression and purification. Protein Expr Purif 116: 42-49.
Young CL, et al. (2012) Recombinant protein expression and purification: A comprehensive review of affinity tags and microbial applications. Biotechnol J 7(5): 620-634.