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Solution structure of the KSHV K3 N-terminal domainSolution structure of the KSHV K3 N-terminal domain
Structural highlights
FunctionMIR1_HHV8P E3 ubiquitin-protein ligase which promotes ubiquitination and subsequent degradation of host MHC-I and CD1D molecules, presumably to prevent lysis of infected cells by cytotoxic T-lymphocytes. Binds target molecules through transmembrane interaction. E3 ubiquitin-protein ligases accept ubiquitin from specific E2 ubiquitin-conjugating enzymes, and then transfer it to target protein. The result of this ubiquitination is the enhancement of the endocytosis of the target chain and the delivery to the lysosome, where it is proteolytically destroyed. Induces ubiquitination not only on lysines, but also on cysteine residues.[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedRING domains are found in a large number of eukaryotic proteins. Most function as E3 ubiquitin-protein ligases, catalyzing the terminal step in the ubiquitination process. Structurally, these domains have been characterized as binding two zinc ions in a stable cross-brace motif. The tumorigenic human gamma-herpesvirus Kaposi's sarcoma-associated herpesvirus encodes a ubiquitin-protein ligase termed K3, which functions as an immune evasion molecule by ubiquitinating major histocompatibility complex class I. K3 possesses at its N terminus a domain related to cellular RING domains but with an altered zinc ligand arrangement. This domain was initially characterized as a plant homeodomain, a structure not previously known to function as an E3. Here, it is conclusively demonstrated that the K3 N-terminal domain is a variant member of the RING domain family and not a plant homeodomain. The domain is found to interact with the cellular ubiquitin-conjugating enzymes UbcH5A to -C and UbcH13, which dock to the equivalent surface as on classical cellular RING domains. Interaction with UbcH13 suggests a possible role for K3 in catalyzing Lys(63)-linked ubiquitination. Solution structure of the Kaposi's sarcoma-associated herpesvirus K3 N-terminal domain reveals a Novel E2-binding C4HC3-type RING domain.,Dodd RB, Allen MD, Brown SE, Sanderson CM, Duncan LM, Lehner PJ, Bycroft M, Read RJ J Biol Chem. 2004 Dec 17;279(51):53840-7. Epub 2004 Sep 30. PMID:15465811[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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