NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Origin of the catalytic activity of bovine seminal ribonuclease against double-stranded RNABovine seminal ribonuclease (RNase) binds, melts, and (in the case of RNA) catalyzes the hydrolysis of double-stranded nucleic acid 30-fold better under physiological conditions than its pancreatic homologue, the well-known RNase A. Reported here are site-directed mutagenesis experiments that identify the sequence determinants of this enhanced catalytic activity. These experiments have been guided in part by experimental reconstructions of ancestral RNases from extinct organisms that were intermediates in the evolution of the RNase superfamily. It is shown that the enhanced interactions between bovine seminal RNase and double-stranded nucleic acid do not arise from the increased number of basic residues carried by the seminal enzyme. Rather, a combination of a dimeric structure and the introduction of two glycine residues at positions 38 and 111 on the periphery of the active site confers the full catalytic activity of bovine seminal RNase against duplex RNA. A structural model is presented to explain these data, the use of evolutionary reconstructions to guide protein engineering experiments is discussed, and a new variant of RNase A, A(Q28L K31C S32C D38G E111G), which contains all of the elements identified in these experiments as being important for duplex activity, is prepared. This is the most powerful catalyst within this subfamily yet observed, some 46-fold more active against duplex RNA than RNase A.
Document ID
20040172719
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Opitz, J. G.
(University of Florida Gainesville 32611-7200, United States)
Ciglic, M. I.
Haugg, M.
Trautwein-Fritz, K.
Raillard, S. A.
Jermann, T. M.
Benner, S. A.
Date Acquired
August 22, 2013
Publication Date
March 24, 1998
Publication Information
Publication: Biochemistry
Volume: 37
Issue: 12
ISSN: 0006-2960
Subject Category
Exobiology
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Exobiology

Available Downloads

There are no available downloads for this record.
No Preview Available