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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2002-12-10
pubmed:abstractText
The marine snail Conus is the sole invertebrate wherein both the vitamin K-dependent carboxylase and its product, gamma-carboxyglutamic acid, have been identified. To examine its biosynthesis of gamma-carboxyglutamic acid, we studied the carboxylase from Conus venom ducts. The carboxylase cDNA from Conus textile has an ORF that encodes a 811-amino-acid protein which exhibits sequence similarity to the vertebrate carboxylases, with 41% identity and approximately 60% sequence similarity to the bovine carboxylase. Expression of this cDNA in COS cells or insect cells yielded vitamin K-dependent carboxylase activity and vitamin K-dependent epoxidase activity. The recombinant carboxylase has a molecular mass of approximately 130 kDa. The recombinant Conus carboxylase carboxylated Phe-Leu-Glu-Glu-Leu and the 28-residue peptides based on residues -18 to +10 of human proprothrombin and proFactor IX with Km values of 420 micro m, 1.7 micro m and 6 micro m, respectively; the Km for vitamin K is 52 micro m. The Km values for peptides based on the sequence of the conotoxin epsilon-TxIX and two precursor analogs containing 12 or 29 amino acids of the propeptide region are 565 micro m, 75 micro m and 74 micro m, respectively. The recombinant Conus carboxylase, in the absence of endogenous substrates, is stimulated up to fivefold by vertebrate propeptides but not by Conus propeptides. These results suggest two propeptide-binding sites in the carboxylase, one that binds the Conus and vertebrate propeptides and is required for substrate binding, and the other that binds only the vertebrate propeptide and is required for enzyme stimulation. The marked functional and structural similarities between the Conus carboxylase and vertebrate vitamin K-dependent gamma-carboxylases argue for conservation of a vitamin K-dependent carboxylase across animal species and the importance of gamma-carboxyglutamic acid synthesis in diverse biological systems.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:volume
269
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6162-72
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:12473112-1-Carboxyglutamic Acid, pubmed-meshheading:12473112-Amino Acid Sequence, pubmed-meshheading:12473112-Animals, pubmed-meshheading:12473112-Blood Coagulation, pubmed-meshheading:12473112-Blotting, Western, pubmed-meshheading:12473112-COS Cells, pubmed-meshheading:12473112-Carbon-Carbon Ligases, pubmed-meshheading:12473112-Cell Line, pubmed-meshheading:12473112-Cloning, Molecular, pubmed-meshheading:12473112-DNA, Complementary, pubmed-meshheading:12473112-Dose-Response Relationship, Drug, pubmed-meshheading:12473112-Genetic Vectors, pubmed-meshheading:12473112-Humans, pubmed-meshheading:12473112-Insects, pubmed-meshheading:12473112-Kinetics, pubmed-meshheading:12473112-Microsomes, pubmed-meshheading:12473112-Molecular Sequence Data, pubmed-meshheading:12473112-Mollusca, pubmed-meshheading:12473112-Open Reading Frames, pubmed-meshheading:12473112-Plasmids, pubmed-meshheading:12473112-Protein Processing, Post-Translational, pubmed-meshheading:12473112-Recombinant Proteins, pubmed-meshheading:12473112-Sequence Homology, Amino Acid, pubmed-meshheading:12473112-Vitamin K
pubmed:year
2002
pubmed:articleTitle
Expression and characterization of recombinant vitamin K-dependent gamma-glutamyl carboxylase from an invertebrate, Conus textile.
pubmed:affiliation
Marine Biological Laboratory, Woods Hole, MA, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.