The dinucleotide-binding site of bovine liver catalase mimics a
catalase mrna-binding protein domain.
Clerch, Linda Biadasz, Angelique Wright, and Donald Massaro.
Lung Biology Laboratory, Departments of Pediatrics and Medicine,
Georgetown University Medical Center, Washington, D.C., 20007
APStracts 2:0232L, 1995.
Rat lung contains protein that interacts with catalase mRNA to form
specific, redox-sensitive RNA-protein complexes. The studies in this
report were aimed at determining whether catalase protein binds its
own RNA. We found that rat catalase RNA binds NADPH-depleted bovine
liver catalase (Sigma) but does not bind bovine liver catalase in the
presence of NADPH. Complex formation between liver catalase and
catalase RNA is competitively eliminated by a CA dinucleotide repeat.
These data suggest the dinucleotide binding site of catalase mimics
or is homologous to a catalase RNA-binding protein domain. These
findings support the hypothesis that a class of RNA-binding proteins
may have evolved from (di)nucleotide binding enzymes (Hentze, TIBS
19:101,1994). When bovine liver catalase from two other commercial
sources (Calbiochem and Boehringer) was used, we could not detect
binding to catalase RNA. We have not yet been able to identify the
basis for this difference. Thus, the physiological importance of our
observation of the NADPH-sensitive protein binding to catalase RNA
cannot be assessed at this time.
Received 28 April 1995; accepted in final form 14 December 1995.
APS Manuscript Number L126-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95