PDBsum entry 3kyh

Protein binding

PDB id: 3kyh

Contents

Protein chains

276 a.a. *

387 a.a. *

* Residue conservation analysis

PDB id:

3kyh

Name:

Protein binding

Title:

Saccharomyces cerevisiae cet1-ceg1 capping apparatus

Structure:

mRNA-capping enzyme subunit beta. Chain: a, b. Fragment: triphosphatase domain. Synonym: polynucleotide 5'-triphosphatase, mRNA 5'-triphosphatase, tpase. Engineered: yes. mRNA-capping enzyme subunit alpha. Chain: c, d. Synonym: mRNA guanylyltransferase, gtp--RNA guanylyltransferase,

Source:

Saccharomyces cerevisiae. Brewer's yeast,lager beer yeast,yeast. Organism_taxid: 4932. Strain: w303-1a. Gene: cet1, p1433, ypl228w. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: ceg1, g2853, ygl130w.

Resolution:

3.00Å R-factor: 0.252 R-free: 0.298

Authors:

C.D.Lima

Key ref:

M.Gu et al. (2010). Structure of the Saccharomyces cerevisiae Cet1-Ceg1 mRNA capping apparatus. Structure, 18, 216-227. PubMed id: 20159466

Date:

06-Dec-09 Release date: 16-Feb-10

Protein chains

O13297  (CET1_YEAST) -  mRNA-capping enzyme subunit beta from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 549 a.a.

Struc: 276 a.a.

Protein chains

Q01159  (MCE1_YEAST) -  mRNA-capping enzyme subunit alpha from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 459 a.a.

Struc: 387 a.a.

Enzyme reactions

• Enzyme class 1: Chains A, B: E.C.3.6.1.74 - mRNA 5'-phosphatase.
• Reaction: a 5'-end triphospho-ribonucleoside in mRNA + H2O = a 5'-end diphospho- ribonucleoside in mRNA + phosphate + H⁺
• Enzyme class 2: Chains C, D: E.C.2.7.7.50 - mRNA guanylyltransferase.
• Reaction: a 5'-end diphospho-ribonucleoside in mRNA + GTP + H⁺ = a 5'-end (5'-triphosphoguanosine)-ribonucleoside in mRNA + diphosphate

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Structure 18:216-227 (2010)

PubMed id: 20159466

Structure of the Saccharomyces cerevisiae Cet1-Ceg1 mRNA capping apparatus.

M.Gu, K.R.Rajashankar, C.D.Lima.

ABSTRACT

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.