The small ubiquitin-related modifier (SUMO) conjugation apparatus usually attaches single SUMO moieties to its substrates, but SUMO chains have also been identified. To better define the biochemical requirements and characteristics of SUMO chain formation, mutations in surface-exposed Lys residues of Arabidopsis SUMO-conjugating enzyme (SCE) were tested for activity. Lys-to-Arg changes in the amino-terminal region of SCE allowed SUMO acceptance from SUMO-activating enzyme and supported substrate mono-sumoylation, but these mutations had significant effects on SUMO chain assembly. We found no indication that SUMO modification of SCE promotes chain formation. A substrate was identified that is modified by SUMO chain addition, showing that SCE can distinguish substrates for either mono-sumoylation or SUMO chain attachment. It is also shown that SCE with active site Cys mutated to Ser can accept SUMO to form an oxyester, but cannot transfer this SUMO moiety onto substrates, explaining a previously known dominant negative effect of this mutation.
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http://dx.doi.org/10.1042/BCJ20170472 | DOI Listing |
Clin Genet
January 2025
Prenatal Diagnosis and Fetal Medicine Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt.
SUMOylation involves covalent attachment of small ubiquitin-like modifier (SUMO) proteins to specific lysine residues on target proteins and regulates various aspects of their function. Sentrin-specific proteases (SENPs) are key players in both the conjugation reaction of SUMO proteins to their targets and the subsequent deconjugation of SUMO-conjugated substrates. Here, we provide the first comprehensive prenatal description of a lethal syndrome linked to a novel homozygous stop-gain variant in SENP7 c.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
December 2024
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China.
Nonstructural protein 3C, a master protease of Picornaviridae, plays a critical role in viral replication by directly cleaving the viral precursor polyprotein to form the viral capsid protein and antagonizing the host antiviral response. Additionally, 3C protease, as a tool enzyme, is involved in regulating polyprotein expression. Here, the 3C mutant gene (3Cm), fused with a small ubiquitin-like modifier (SUMO) tag at the N-terminal and featuring a mutation at position 127, was inserted into the cold-shock plasmid pCold of Escherichia coli for expression.
View Article and Find Full Text PDFProtein Sci
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.
After overexpression in a suitable host, recombinant protein purification often relies on affinity (e.g., poly-histidine) and solubility-enhancing (e.
View Article and Find Full Text PDFJ Virol
December 2024
Biological Sciences, Towson University, Towson, Maryland, USA.
Unlabelled: Kaposi's sarcoma herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma and is associated with primary effusion lymphoma (PEL), multicentric Castleman's disease, and two inflammatory diseases. KSHV-associated cancers are primarily associated with genes expressed during latency, while other pathologies are associated with lytic gene expression. The major lytic switch of the virus, Replication and Transcription Activator (RTA), interacts with cellular machinery to co-opt the host ubiquitin proteasome system to evade the immune response as well as activate the program of lytic replication.
View Article and Find Full Text PDFBiochemistry
December 2024
Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India.
The conventional idea that a well-defined protein structure governs its functions is being challenged by the evolving significance of conformational flexibility and disorder in influencing protein activity. Here, we focus on the Small Ubiquitin-like MOdifier 1 (SUMO1) protein, a post-translational modifier, which binds various target proteins during the process of SUMOylation. We present evidence supporting the presence of both folded and "ordered" molten globule (MG) states in SUMO1 under physiological conditions.
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