1I9T

CRYSTAL STRUCTURE OF THE OXIDIZED RNA TRIPHOSPHATASE DOMAIN OF MOUSE MRNA CAPPING ENZYME

Summary for 1I9T

• Entry DOI: 10.2210/pdb1i9t/pdb
• Related: 1I9S
• Descriptor: MRNA CAPPING ENZYME, SULFATE ION, CACODYLATE ION, ... (6 entities in total)
• Functional Keywords: rna triphosphatase domain, mrna capping enzyme, cysteine sulfenic acid, hydrolase
• Biological source: Mus musculus (house mouse)
• Cellular location: Nucleus: O55236
• Total number of polymer chains: 1
• Total formula weight: 24713.18

Authors

Changela, A.,Ho, C.K.,Martins, A.,Shuman, S.,Mondragon, A. (deposition date: 2001-03-20, release date: 2001-05-23, Last modification date: 2023-11-15)

Primary citation

Changela, A.,Ho, C.K.,Martins, A.,Shuman, S.,Mondragon, A.
Structure and mechanism of the RNA triphosphatase component of mammalian mRNA capping enzyme.
EMBO J., 20:2575-2586, 2001

PubMed Abstract: The 5' capping of mammalian pre-mRNAs is initiated by RNA triphosphatase, a member of the cysteine phosphatase superfamily. Here we report the 1.65 A crystal structure of mouse RNA triphosphatase, which reveals a deep, positively charged active site pocket that can fit a 5' triphosphate end. Structural, biochemical and mutational results show that despite sharing an HCxxxxxR(S/T) motif, a phosphoenzyme intermediate and a core alpha/beta-fold with other cysteine phosphatases, the mechanism of phosphoanhydride cleavage by mammalian capping enzyme differs from that used by protein phosphatases to hydrolyze phosphomonoesters. The most significant difference is the absence of a carboxylate general acid catalyst in RNA triphosphatase. Residues conserved uniquely among the RNA phosphatase subfamily are important for function in cap formation and are likely to play a role in substrate recognition.

PubMed: 11350947
DOI: 10.1093/emboj/20.10.2575

Experimental method

X-RAY DIFFRACTION (1.7 Å)