Isolation and structural characterization of a cDNA clone encoding rat gastric intrinsic factor.

Content Provider	Semantic Scholar
Author	Dieckgraefe, Brian K. Seetharam, Bellur Banaszak, Leonard J. Leykam, Joseph F. Alpers, David H.
Copyright Year	1988
Abstract	Rat intrinsic factor (IF) has been purified and proteolytic fragments were sequenced. A cDNA library was constructed from size-enriched gastric poly(A)+ RNA and screened for IF-positive clones by antibody and synthetic oligodeoxynucleotide probe hybridization. An IF clone was isolated and sequenced, revealing a predicted primary amino acid sequence in the coding region of 421 amino acids and a putative signal sequence of 22 amino acids. The primary translation product of IF produced in a cell-free translation system displayed cobalamin (Cbl)-binding activity without proteolytic processing or glycosylation. The amino-terminal region of IF showed significant secondary structural and hydropathic homologies with the nucleotide-binding domain in NAD-dependent oxidoreductases. Alignment of the first 80 residues of IF, following the signal peptide, demonstrated homology with the nucleotide-binding domain of cytoplasmic malate dehydrogenase. Based on these data, we propose a model of IF tertiary structure in which the Cbl-binding domain resides in the NH2-terminal half of the protein.
Starting Page	46
Ending Page	50
Page Count	5
File Format	PDF HTM / HTML
DOI	10.1073/pnas.85.1.46
Alternate Webpage(s)	http://www.pnas.org/content/85/1/46.full.pdf
PubMed reference number	3422425
Alternate Webpage(s)	https://doi.org/10.1073/pnas.85.1.46
Journal	Medline
Volume Number	85
Issue Number	1
Journal	Proceedings of the National Academy of Sciences of the United States of America
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article