Modomics - A Database of RNA Modifications

ID Card:

Full name: mRNA-capping enzyme subunit alpha
Synonym: GTase, Mce1
GI: 1322697
Orf: CEG1
COG: COG5226
UniProt: Q01159
Structures: | 3KYH |
Alpha Fold Predicted Structure: AF-Q01159-F1
Enzyme type: guanylyltransferase
Position of modification - modification: m:0 - m7GpppN


PDB Structures:


3KYH

Structure Description:

Title:
Classification:
Technique:

Abstract of the PDB Structure's related Publication:

The 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.

Download RCSB-PDB Structures:

Pdb Files   3KYH.pdb  
Pdbx/mmCIF Files   3KYH.cif  


Protein sequence:

MVLAMESRVAPEIPGLIQPGNVTQDLKMMVCKLLNSPKPTKTFPGSQPVSFQHSDVEEKLLAHDYYVCEKTDGLRVLMFIVINPVTGEQGCFMIDRENNYYLVNGFRFPRLPQKKKEELLETLQDGTLLDGELVIQTNPMTKLQELRYLMFDCLAINGRCLTQSPTSSRLAHLGKEFFKPYFDLRAAYPNRCTTFPFKISMKHMDFSYQLVKVAKSLDKLPHLSDGLIFTPVKAPYTAGGKDSLLLKWKPEQENTVDFKLILDIPMVEDPSLPKDDRNRWYYNYDVKPVFSLYVWQGGADVNSRLKHFDQPFDRKEFEILERTYRKFAELSVSDEEWQNLKNLEQPLNGRIVECAKNQETGAWEMLRFRDDKLNGNHTSVVQKVLESINDSVSLEDLEEIVGDIKRCWDERRANMAGGSGRPLPSQSQNATLSTSKPVHSQPPSNDKEPKYVDEDDWSD

Comments:

S.cerevisiae Triphosphatase Cet1 and RNA guanylyltransferase (Ceg1) interact in vivo and in vitro to form a bifunctional mRNA capping enzyme complex (Haussmann et al. 2001 ) . Indeed, an Essential Function of Saccharomyces cerevisiae RNA Triphosphatase Cet1 Is to Stabilize RNA Guanylyltransferase Ceg1 against thermal inactivation. The guanylyltransferase activity of the mRNA capping -enzyme catalyzes the transfer of GMP from GTP to the 5' terminus of mRNA. In S.cerevisiae the activity is carried on the alpha subunit of the capping enzyme, the product of the CEG1 gene (Yamagishi et al. 1995) . 5' guanine - N7 cap is essential for all eukaryotic organisms examined thus far and is the first co-transcriptional modification of cellular pre-messenger RNA. It represses RNA polymerase II transcription in vivo, suggesting a bidirectional flow of information between capping and transcription.




Reaction Substrate SubstrateType Position (Anti)Codon Modified (Anti)Codon Amino Acid Change Transcript Name Transcript Region Cellular Localization References
ppN:GpppN RNA mRNA 0 5' - END Nucleoplasm 3029058   

Alpha Fold Predicted Structure:






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Protein sequence:

M V L A M E S R V A P E I P G L I Q P G N V T Q D L K M M V C K L L N S P K P T K T F P G S Q P V S F Q H S D V E E K L L A H D Y Y V C E K T D G L R V L M F I V I N P V T G E Q G C F M I D R E N N Y Y L V N G F R F P R L P Q K K K E E L L E T L Q D G T L L D G E L V I Q T N P M T K L Q E L R Y L M F D C L A I N G R C L T Q S P T S S R L A H L G K E F F K P Y F D L R A A Y P N R C T T F P F K I S M K H M D F S Y Q L V K V A K S L D K L P H L S D G L I F T P V K A P Y T A G G K D S L L L K W K P E Q E N T V D F K L I L D I P M V E D P S L P K D D R N R W Y Y N Y D V K P V F S L Y V W Q G G A D V N S R L K H F D Q P F D R K E F E I L E R T Y R K F A E L S V S D E E W Q N L K N L E Q P L N G R I V E C A K N Q E T G A W E M L R F R D D K L N G N H T S V V Q K V L E S I N D S V S L E D L E E I V G D I K R C W D E R R A N M A G G S G R P L P S Q S Q N A T L S T S K P V H S Q P P S N D K E P K Y V D E D D W S D

Secondary Structure Alphabet

  • G: 3-turn helix (310helix)
  • H: α-helix
  • I: 𝝅-helix (5 - turn helix)
  • T: Hydrogen Bonded Turn
  • B: β-sheet
  • S: Bend
  • C: Coil (residues not present in any of the above conformations)
  • N: Not assigned

Download PDB Structures & DSSP Secondary Structures:

Alpha Fold Pdb Files   AF-Q01159-F1.pdb  
Alpha Fold Pdbx/mmCIF Files   AF-Q01159-F1.cif  
DSSP Secondary Structures   Q01159.dssp  





Publications:

Title Authors Journal Details PubMed Id DOI
mRNA capping enzyme. Isolation and characterization of the gene encoding mRNA guanylytransferase subunit from Saccharomyces cerevisiae. Shibagaki Y, Itoh N, Yamada H, Nagata S, Mizumoto K J Biol Chem [details] 1315757 -
Isolation of temperature-sensitive mutants for mRNA capping enzyme in Saccharomyces cerevisiae. Yamagishi M, Mizumoto K, Ishihama A Mol Gen Genet [details] 7500935 -
Messenger RNA guanylyltransferase from Saccharomyces cerevisiae. Large scale purification, subunit functions, and subcellular localization. Itoh N, Yamada H, Kaziro Y, Mizumoto K J Biol Chem [details] 3029058 -
Structure of the Saccharomyces cerevisiae Cet1-Ceg1 mRNA capping apparatus. Gu M, Rajashankar KR, Lima CD Structure [details] 20159466 -
An essential function of Saccharomyces cerevisiae RNA triphosphatase Cet1 is to stabilize RNA guanylyltransferase Ceg1 against thermal inactivation. Hausmann S, Ho CK, Schwer B, Shuman S... J Biol Chem [details] 11463793 -

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