Abstract
Human AMPD2 cDNA clones have been isolated from T-lymphoblast and placental lambda gt11 libraries utilizing a previously cloned rat partial AMPD2 cDNA as the probe. Alignment analysis of all cDNA clones indicates the presence of intervening sequences in several placental isolates. This has been confirmed by sequencing human AMPD2 genomic clones. Intervening sequences can be removed from the cDNA clones by restriction with endonucleases at unique sites within the proposed open reading frame. This results in a 3292-base pair cDNA proposed to contain the entire AMPD2 open reading frame, which would encode a 760-amino acid polypeptide with a predicted subunit molecular mass of 88.1 kDa. Nucleotide and predicted amino acid comparisons with the 264 base pairs of proposed coding sequences in the rat AMPD2 cDNA demonstrate 91% similarity and identity, respectively. A comparison of the predicted human AMPD1 and AMPD2 polypeptides demonstrates homology in their C-terminal domains. Included in this region is the conserved motif, SLSTDDP, proposed to be part of the catalytic site of all AMP deaminases. In contrast, the predicted N-terminal domains of the human AMPD1 and AMPD2 polypeptides are unique. When placed in a prokaryotic expression vector, the human AMPD2 cDNA expresses AMP deaminase activity which can be precipitated with polyclonal antisera specific for isoform L.
Highlights
From the Departmentof Cellular Biology and Anatomy, TheMedical College of Wisconsin, Milwaukee, Wisconsin53226 and the $Department of Medicine, University of Pennsylvania Schoolof Medicine, Philadelphia, Pennsylvania 19104-4283
This results in a 3292-base pair cDNA proposed to contain the entire AMPD2 open reading frame, which would encode a 760-amino acid polypeptide with a predicted subunit molecular mass of 88.1 kDa
A single nonsense mutation in the human AMPDl gene has been identified in 11patients presenting with a myopathy and an inherited skeletal muscle deficiency of isoform M [10]
Summary
Kemic cell line and cloned into the X2001 phage vector, was obtained from Dr Richard Baer (Southwestern Medical Center, Dallas, TX). The large block of nucleotide similarity inthe 3' two-thirds of the human AMPDl and AMPDB cDNAs described above would encode a highly homologous stretch of amino acids, 62% (314/505), spanning residues 232 to 736 in the AMPDl polypeptide and residues 228 to 732 inthe AMPD2 polypeptide (see Fig. 5). Included within this conserved domain of amino acids are the predicted 88 residues from all cloned AMPD cDNA sequences, i.e. yeast, rat, and human [12]. In order to examine whether a similar profile of AMPD
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
