Linked Life Data

9473487

Source:http://linkedlifedata.com/resource/pubmed/id/9473487

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-3-16
pubmed:databankReference
pubmed:abstractText
Previous studies demonstrated that the mammalian mRNA capping enzyme is a bifunctional enzyme containing RNA 5'-triphosphatase and mRNA guanylyl-transferase activities in a single polypeptide. In yeast, both the above activities are separated into two different subunits, alpha and beta, the genes for which we have cloned recently. It is thus interesting to compare the structural and functional relationships between the mammalian and yeast capping enzymes. Here we isolated two human cDNAs encoding mRNA capping enzymes termed hCAP1a and hCAP1b which encode 597 and 541 amino acids, respectively. They are different only at the region coding for the C-terminal portion of the enzyme. Comparison of the deduced amino acid sequences with other cellular and viral capping enzymes showed that all the regions conserved among mRNA guanylyltransferases are observed in our clones except one conserved C-terminal region which was absent in the hCAP1b protein. The purified recombinant hCAP1a gene product, hCAP1a, exhibited both RNA 5'-triphosphatase and mRNA guanylyltransferase activities. Deletion mutant analysis of hCAP1a showed that the N-terminal 213 amino acid fragment containing a tyrosine specific protein phosphatase motif catalyzed the RNA 5'-triphosphatase activity and the C-terminal 369 amino acid fragment exhibited the mRNA guanylyltransferase activity. On the other hand, hCAP1b showed RNA 5'-triphosphatase activity, but neither enzyme-GMP covalent complex formation nor cap structure formation was detected.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-291X
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
243
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
101-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Cloning and characterization of two human cDNAs encoding the mRNA capping enzyme.
pubmed:affiliation
Department of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
pubmed:publicationType
Journal Article, Comparative Study