Structural highlights
Function[CET1_YEAST] First step of mRNA capping. Converts the 5'-triphosphate end of a nascent mRNA chain into a diphosphate end.[1] [MCE1_YEAST] Second step of mRNA capping. Transfer of the GMP moiety of GTP to the 5'-end of RNA via an enzyme-GMP covalent reaction intermediate. 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 PubMedThe 5' guanine-N7 cap is the first cotranscriptional modification of messenger RNA. In Saccharomyces cerevisiae, the first two steps in capping are catalyzed by the RNA triphosphatase Cet1 and RNA guanylyltransferase Ceg1, which form a complex that is directly recruited to phosphorylated RNA polymerase II (RNAP IIo), primarily via contacts between RNAP IIo and Ceg1. A 3.0 A crystal structure of Cet1-Ceg1 revealed a 176 kDa heterotetrameric complex composed of one Cet1 homodimer that associates with two Ceg1 molecules via interactions between the Ceg1 oligonucleotide binding domain and an extended Cet1 WAQKW amino acid motif. The WAQKW motif is followed by a flexible linker that would allow Ceg1 to achieve conformational changes required for capping while maintaining interactions with both Cet1 and RNAP IIo. The impact of mutations as assessed through genetic analysis in S. cerevisiae is consonant with contacts observed in the Cet1-Ceg1 structure. Structure of the Saccharomyces cerevisiae Cet1-Ceg1 mRNA capping apparatus.,Gu M, Rajashankar KR, Lima CD Structure. 2010 Feb 10;18(2):216-27. PMID:20159466[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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