5k7u | pdb_00005k7u
Crystal structure of the catalytic domains of Mettl3/Mettl14 complex with SAM
Structural highlights
FunctionMTA70_HUMAN N6-methyltransferase that methylates adenosine residues of some RNAs and acts as a regulator of the circadian clock, differentiation of embryonic stem cells and primary miRNA processing. N6-methyladenosine (m6A), which takes place at the 5'-[AG]GAC-3' consensus sites of some mRNAs, plays a role in the efficiency of mRNA splicing, processing, translation efficiency, editing and mRNA stability (PubMed:22575960, PubMed:24284625, PubMed:25719671, PubMed:25799998, PubMed:26321680, PubMed:26593424, PubMed:9409616). M6A regulates the length of the circadian clock: acts as a early pace-setter in the circadian loop by putting mRNA production on a fast-track for facilitating nuclear processing, thereby providing an early point of control in setting the dynamics of the feedback loop (By similarity). M6A also acts as a regulator of mRNA stability: in embryonic stem cells (ESCs), m6A methylation of mRNAs encoding key naive pluripotency-promoting transcripts results in transcript destabilization, promoting differentiation of ESCs (By similarity). M6A also takes place in other RNA molecules, such as primary miRNA (pri-miRNAs) (PubMed:25799998). Mediates methylation of pri-miRNAs, marking them for recognition and processing by DGCR8 (PubMed:25799998).[UniProtKB:Q8C3P7][1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedN(6)-methyladenosine (m(6)A) is a prevalent, reversible chemical modification of functional RNAs and is important for central events in biology. The core m(6)A writers are Mettl3 and Mettl14, which both contain methyltransferase domains. How Mettl3 and Mettl14 cooperate to catalyze methylation of adenosines has remained elusive. We present crystal structures of the complex of Mettl3/Mettl14 methyltransferase domains in apo form as well as with bound S-adenosylmethionine (SAM) or S-adenosylhomocysteine (SAH) in the catalytic site. We determine that the heterodimeric complex of methyltransferase domains, combined with CCCH motifs, constitutes the minimally required regions for creating m(6)A modifications in vitro. We also show that Mettl3 is the catalytically active subunit, while Mettl14 plays a structural role critical for substrate recognition. Our model provides a molecular explanation for why certain mutations of Mettl3 and Mettl14 lead to impaired function of the methyltransferase complex. Structural Basis for Cooperative Function of Mettl3 and Mettl14 Methyltransferases.,Wang P, Doxtader KA, Nam Y Mol Cell. 2016 Jul 21;63(2):306-17. doi: 10.1016/j.molcel.2016.05.041. Epub 2016 , Jun 30. PMID:27373337[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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