6ict
From Proteopedia
Structure of SETD3 bound to SAH and methylated actin
Structural highlights
Disease[ACTB_HUMAN] Defects in ACTB are a cause of dystonia juvenile-onset (DYTJ) [MIM:607371]. DYTJ is a form of dystonia with juvenile onset. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYTJ patients manifest progressive, generalized, dopa-unresponsive dystonia, developmental malformations and sensory hearing loss.[1] Defects in ACTB are the cause of Baraitser-Winter syndrome type 1 (BRWS1) [MIM:243310]. A rare developmental disorder characterized by the combination of congenital ptosis, high-arched eyebrows, hypertelorism, ocular colobomata, and a brain malformation consisting of anterior-predominant lissencephaly. Other typical features include postnatal short stature and microcephaly, intellectual disability, seizures, and hearing loss.[2] Function[SETD3_HUMAN] Histone methyltransferase that methylates 'Lys-36' of histone H3 (H3K36me). H3 'Lys-36' methylation represents a specific tag for epigenetic transcriptional activation (By similarity). [ACTB_HUMAN] Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. Publication Abstract from PubMedSETD3 is a member of the SET (Su(var)3-9, Enhancer of zeste, and Trithorax) domain protein superfamily and plays important roles in hypoxic pulmonary hypertension, muscle differentiation, and carcinogenesis. Previously, we identified SETD3 as the actin-specific methyltransferase that methylates the N3 of His73 on beta-actin (Kwiatkowski et al., 2018). Here, we present two structures of S-adenosyl-L-homocysteine-bound SETD3 in complex with either an unmodified beta-actin peptide or its His-methylated variant. Structural analyses, supported by biochemical experiments and enzyme activity assays, indicate that the recognition and methylation of beta-actin by SETD3 are highly sequence specific, and that both SETD3 and beta-actin adopt pronounced conformational changes upon binding to each other. In conclusion, this study is the first to show a catalytic mechanism of SETD3-mediated histidine methylation on beta-actin, which not only throws light on the protein histidine methylation phenomenon but also facilitates the design of small molecule inhibitors of SETD3. Structural insights into SETD3-mediated histidine methylation on beta-actin.,Guo Q, Liao S, Kwiatkowski S, Tomaka W, Yu H, Wu G, Tu X, Min J, Drozak J, Xu C Elife. 2019 Feb 20;8. pii: 43676. doi: 10.7554/eLife.43676. PMID:30785395[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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